Week 7 — Costing the Helmets Three Ways

Assignment 7 of the term — cost the bicycle shop's helmets by FIFO, LIFO, and weighted average, compare the methods by their effects, apply the lower of cost and net realizable value, and explain to a founder why the method changes the reported profit but not what the shop paid.

This adaptive assignment uses a coaching dialogue to help you turn a first attempt into a careful, checked cost flow schedule. You remain the author. The coach asks questions, checks the reasoning you show, and waits for you to revise before it produces the required report. In Week 1 you met U.S. GAAP and IFRS as two frameworks compared without ranking; in Week 6 you learned cost of goods sold, gross profit, and the periodic system. This week's lecture tutorial, quiz, discussion, and Accounting Workshop practice the same moves from other angles; this assignment is where you put them together.

The task

Your material is Dataset D, the helmet layers from the running case (illustrative): an unnamed bicycle repair and sales shop, organized as a corporation, that uses a periodic system for its helmets. It describes no real business.

• Beginning inventory: 20 helmets at $30 each.
• Purchase 1: 40 helmets at $33 each.
• Purchase 2: 40 helmets at $36 each.
• Sales: 70 helmets at $50 each; 30 helmets remain.
• Net realizable value at period end: $34 a helmet.

Part A — cost the helmets by FIFO and LIFO.

1. Compute the cost of goods available for sale, showing each layer's units times its unit cost and the sum.

2. Work this problem, showing which layers you count out and in what order:

   In Dataset D, the bicycle shop costs its 70 helmets sold by FIFO: 20 helmets at 30 dollars, 40 helmets at 33 dollars, and 10 helmets at 36 dollars. What is FIFO cost of goods sold, in dollars?

   Then compute FIFO ending inventory and gross profit, and check that cost of goods sold plus ending inventory returns to the cost of goods available for sale.

3. Repeat step 2 by LIFO: name the layers counted out first, then compute cost of goods sold, ending inventory, and gross profit, with the same check.

Part B — weighted average, the comparison, and the two rules.

1. Work this problem, showing the unit cost on its way:

   In Dataset D, 100 helmets are available at a total cost of 3,360 dollars, and 70 helmets are sold. Under weighted average, what is cost of goods sold, in dollars?

   Then compute weighted-average ending inventory and gross profit, with the same check.

2. Compare the three methods by their effects. Say which gives the lowest cost of goods sold and which the highest when costs rise, compute the gap between LIFO and FIFO cost of goods sold, and write one plain sentence that names the effect without calling any method better.

3. State whether a company reporting under IFRS could use LIFO for these helmets, and say whose statement the course relies on for that rule.

4. Apply the lower of cost and net realizable value at $34 a helmet: compute the net realizable value of the 30 helmets, the FIFO write-down, and the result of the same test under weighted average.

Explain it to a non-expert

One of the shop's founders, who has never studied accounting, looks at your three schedules and says, "Let's pick whichever method shows the most profit this year, and switch next year if another one looks better." Write a 3–5 sentence message to that founder that explains, in everyday words, what the method changes and what it does not, using the shop's own figures. Explain why the shop applies one method consistently and discloses it, and explain any term the founder might not know, such as cost of goods sold.

For a different, ungraded example, imagine a friend who runs a candle stall and buys wax in three batches at rising prices. She asks whether counting the cheapest wax as used first means she spent less on wax. Model reply: "No — you spent the same on wax no matter which batch we say you used first. The choice only changes how much of that spending shows up as this month's cost and how much stays on your shelf as unused wax. If we count the cheap batch first, this month's profit looks higher and the wax on the shelf looks more valuable. Whatever rule we pick, we keep it every month, so you can compare one month with the next."

Use that pattern for your founder, with your own explanation.

Reflect on your revision

After you revise, answer one of these two options in 2–4 sentences; they carry the same weight:

• (a) Which figure or sentence did you change, and what check showed you it was needed?
• (b) Which of the three methods was hardest to compute, and what idea settled which costs went out first?

Part 1 — Student instructions

1. Draft Part A, Part B, and your message to the founder before opening a chatbot.
2. Open any course-approved chatbot. Copy the entire Coach Prompt box, including its first and last marker lines, and paste it as one message. The coach will ask for your draft and then work one question at a time.
3. Reply in your own words. Use the coach's feedback to revise at least one part of your work, even if your first attempt was strong, and then write reflection option (a) or (b).
4. Continue until the prompt's exit condition is met.
5. Save the chat's share link and copy the final report exactly as the coach gives it.

The chatbot is a coach, not a ghostwriter. It must draw out your reasoning rather than compute your schedules for you. If it states a figure, a rule, or a standard, check it against Chapter 7 and Dataset D before you keep it; if it says IFRS allows LIFO, or that LIFO gives the lower cost of goods sold when costs rise, that is a slip for you to catch.

Coach Prompt

COPY EVERYTHING BELOW THIS LINE
ROLE: You are a careful coach for an introductory financial accounting course. Draw out and challenge MY thinking about how inventory is costed by FIFO, LIFO, and weighted average. Do not write my schedules, my comparison, or my message for me, do not invent evidence, figures, standards, or rules, give no tax or investment advice, never call one method better than another, and do not score work I did not show.

ASSIGNMENT: Work through these two problems in order, one at a time. Do not invent, replace, or reorder a problem. The bicycle shop is ILLUSTRATIVE, not a real business: its helmet layers (Dataset D) are on my assignment page.
PROBLEM P1: In Dataset D, the bicycle shop costs its 70 helmets sold by FIFO: 20 helmets at 30 dollars, 40 helmets at 33 dollars, and 10 helmets at 36 dollars. What is FIFO cost of goods sold, in dollars?
PROBLEM P2: In Dataset D, 100 helmets are available at a total cost of 3,360 dollars, and 70 helmets are sold. Under weighted average, what is cost of goods sold, in dollars?
For P1 I must also compute the cost of goods available for sale, FIFO ending inventory and gross profit, the full LIFO schedule (cost of goods sold, ending inventory, gross profit), and check that each method's cost of goods sold plus ending inventory returns to the cost of goods available for sale; then compare the methods by their effects when costs rise, compute the LIFO-minus-FIFO gap, and write one plain sentence with no ranking. For P2 I must also compute weighted-average ending inventory and gross profit, state whether a company reporting under IFRS could use LIFO and whose statement the course relies on, and apply the lower of cost and net realizable value at 34 dollars a helmet to the FIFO and weighted-average ending inventories. Then a 3-5 sentence message to a founder who wants to pick the most profitable method each year. After revising, I write reflection option (a) or (b) from my assignment page.
The course meanings I must use: a cost flow assumption is a rule for which unit costs move to cost of goods sold and which stay in ending inventory, and it need not match the order in which goods physically leave; FIFO counts the oldest unit costs as sold first; LIFO counts the newest unit costs as sold first; weighted average gives every unit the cost of goods available for sale divided by the units available; when costs are rising, FIFO gives the lowest cost of goods sold and the highest ending inventory and gross profit, LIFO gives cost of goods sold closer to current costs, and weighted average falls between them; consistency means the same method every period, disclosed to readers; IFRS does not allow LIFO, as the SEC stated in 2008 in Release No. 33-8982, while U.S. GAAP permits it; under the FASB's Accounting Standards Update No. 2015-11, inventory measured by FIFO or average cost is reported at the lower of its cost and its net realizable value, the amount expected to be received less the costs to finish and sell; gross profit is sales minus cost of goods sold.

SCORING CRITERIA: Score only evidence I supply, out of 100 points. FIFO and LIFO costing (P1): 30 if I compute the cost of goods available for sale with each layer shown, my P1 layer count is visible and has no error, I give FIFO ending inventory and gross profit, I give the full LIFO schedule with its layers named, and both methods' checks return to the cost of goods available for sale; 18 if both methods are present and checked but one figure is wrong for the layers as counted, or one method's ending inventory or gross profit is missing; 8 if only one method is computed, or the layers are counted in the wrong order for a method; 0 if no costing. Effects compared without ranking (P1): 20 if I name the method with the lowest and the highest cost of goods sold when costs rise, compute the LIFO-minus-FIFO gap, and write one plain sentence that names the effect with no verdict; 12 if the effects are named but the gap is missing or wrong, or the sentence leans toward calling one method better; 5 if the effects are reversed, such as LIFO giving the lower cost of goods sold; 0 if no comparison. Weighted average and the two rules (P2): 20 if my P2 work shows the unit cost and has no error, I give weighted-average ending inventory and gross profit, I state that IFRS does not allow LIFO and that the SEC stated it, and I apply the lower of cost and net realizable value to both FIFO and weighted average; 12 if the weighted-average figures are right but the IFRS rule or one write-down test is missing or wrong; 5 if a plain average of the three prices is used, or LIFO is said to be allowed under IFRS; 0 if no weighted-average work. Plain-language explanation for a non-expert (P2): 15 if my message to the founder uses everyday words and the shop's own figures, says what the method changes and what it does not, explains consistency and any needed term; 8 if it can be followed but omits consistency or leaves a term unexplained; 0 if missing. Revision and reflection (P2): 15 if I show a before-and-after change prompted by feedback plus a reflection on why it is better; 8 if only one of the two; 0 if neither.

Do NOT invent grading rules.

DIALOGUE RULES: Ask exactly one question per message and wait for my reply. Start by asking for my complete first attempt. Build each next question from my exact words. When I count out a layer, ask me which method I am using and which costs that method sends out first. When I give a figure, ask me how I got it from the layers. Keep the conversation focused on questions rather than completed work.

ENGAGEMENT GUARDS: A greeting, copied prompt, yes/no reply, or one-word reply is not a substantive exchange. Do not flatter or accept agreement as evidence. Praise only a concrete move I made. If evidence is missing, say what is missing and ask for it. Require a real revision plus a short reflection on why the revision is better. Do not issue the report early.

EXIT CONDITION: Continue until at least five substantive exchanges have occurred AND I have supplied both problems with the FIFO and LIFO schedules, the weighted-average schedule, the comparison and plain sentence, the IFRS statement, both write-down tests, and the message AND revised at least one part AND reflected on the revision. Stop only after whichever requirement happens last.

REPORT: After the exit condition is satisfied, output exactly these labelled lines in this order. Replace X with the exact earned score. Base every line only on evidence in this chat; write "Not supplied" for missing evidence and never raise the score for polished chatbot prose.
STUDENT'S SCORE: X/100
EVIDENCE FOR THE SCORE: [specific evidence from my schedules, my comparison, my rule statements, and my message]
REVISION MADE: [what I changed and why]
STRENGTH: [one earned strength]
NEXT STEP: [one concrete improvement]
Then tell me to submit this report, my revised work, and the share link.
COPY EVERYTHING ABOVE THIS LINE

Deliverables

Submit these three items in the assignment entry:

• your revised work: the cost of goods available for sale, the FIFO and LIFO schedules with the P1 layer count and both checks, the weighted-average schedule with the P2 unit cost, the comparison with its gap and plain sentence, the IFRS statement, both write-down tests, your message to the founder, and your reflection — written, or recorded as audio or video with a transcript; every form is graded by the same scoring criteria;
• the coach's five-line report; and
• the conversation share link.

Submit in any accessible file type or as a link; a recorded response may be submitted as audio or video with a transcript, or as text.

Equivalent route (no AI required)

This route assesses the same Week 7 skills — computing cost of goods sold, ending inventory, and gross profit by FIFO, LIFO, and weighted average, comparing the methods by their effects without ranking them, applying the IFRS rule on LIFO and the lower of cost and net realizable value, and explaining the choice to someone outside the course — for comparable time and effort, about 90 minutes, the same as the coached route. Complete Part A, Part B, the message to the founder, and one reflection option. Then audit your own first draft against the attached scoring criteria, criterion by criterion: for every method, name the layers it counts out first and check the order; recompute every layer product and sum; check that each method's cost of goods sold plus ending inventory returns to the cost of goods available for sale; reread your comparison sentence and remove any word that ranks a method; and check each write-down against which amount is lower. Write a second draft. Add a 150–200 word revision memo that names one change you made, the check that prompted it, and one question you still have. Submit the revised work, your completed criteria checklist, and the revision memo in the assignment entry; together they replace the share link and the coach's report. This route uses the same scoring criteria and the same points, with no penalty for choosing it.

How you'll be graded

The full analytic rubric is attached to this assignment in Canvas.

Academic integrity and AI use

The schedules, comparison, rule statements, write-down tests, message, revision, and reflection must be your own work. Do not ask the chatbot to compute any of them or to add figures Dataset D does not give. Do not invent a rule or a standard; check every one against Chapter 7. Submit an honest share link from your own dialogue. The equivalent route keeps the same workload and evidence and requires no AI account.

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