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The total manufacturing cost of product P is equal to the sum of produ 16 Apr 2019, 09:29
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C
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55% (hard)

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60% (01:51) correct 40% (02:04) wrong based on 239 sessions

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The total manufacturing cost of product P is equal to the sum of product P's fixed cost and line cost. If the line cost of manufacturing P decreased by 10% in March compared to previous month, by what percent did the total cost of manufacturing product P change in that March over the previous month?

(1) The fixed cost of manufacturing product P increased by 15% in March compared to previous month.
(2) Before the changes in March, the fixed cost of manufacturing product P was 10 times the line cost of manufacturing product P.
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C
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lifeforhuskar
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The total manufacturing cost of product P is equal to the sum of produ 13 Jun 2019, 08:00
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i picked B, why its called fixed cost , when it can change as well
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sandave
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The total manufacturing cost of product P is equal to the sum of produ 16 Apr 2019, 10:27
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The total manufacturing cost of product P is equal to the sum of product P's fixed cost and line cost. If the line cost of manufacturing P decreased by 10% in March compared to previous month, by what percent did the total cost of manufacturing product P change in that March over the previous month?

(1) The fixed cost of manufacturing product P increased by 15% in March compared to previous month.
(2) Before the changes in March, the fixed cost of manufacturing product P was 10 times the line cost of manufacturing product P.


Sol

Given cost of product = P

F= fixed cost
L= line cost

Feb

P=L+F

Mar

P=F'(some new F or same )+ 0.9L


1st statement

Fixed cost increased hence

F' =1.15*F

P=1.15F +0.9L

Month on month growth = this month/last month

So

(1.15F + 0.9L) / (F +L)

Since F and L are unknowns hence value can be anything
So A and D ruled out

2nd Statement

F=10L

But F' is not know hence month on month cannot be calculated

So B ruled out


Both the statement


(1.15*10L +0.9L)/(10L+L)= 1=127

A single value hence C

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The total manufacturing cost of product P is equal to the sum of produ 16 Jun 2026, 01:07
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S2 says " Before the changes in March, the fixed cost of manufacturing product P was 10 times the line cost of manufacturing product P". How are we assuming this relationship of F=10L in March? Shouldn't it be (1.15*F +0.9L)/(10L+L) so E?
sandave
The total manufacturing cost of product P is equal to the sum of product P's fixed cost and line cost. If the line cost of manufacturing P decreased by 10% in March compared to previous month, by what percent did the total cost of manufacturing product P change in that March over the previous month?

(1) The fixed cost of manufacturing product P increased by 15% in March compared to previous month.
(2) Before the changes in March, the fixed cost of manufacturing product P was 10 times the line cost of manufacturing product P.


Sol

Given cost of product = P

F= fixed cost
L= line cost

Feb

P=L+F

Mar

P=F'(some new F or same )+ 0.9L


1st statement

Fixed cost increased hence

F' =1.15*F

P=1.15F +0.9L

Month on month growth = this month/last month

So

(1.15F + 0.9L) / (F +L)

Since F and L are unknowns hence value can be anything
So A and D ruled out

2nd Statement

F=10L

But F' is not know hence month on month cannot be calculated

So B ruled out


Both the statement


(1.15*10L +0.9L)/(10L+L)= 1=127

A single value hence C

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The total manufacturing cost of product P is equal to the sum of produ 16 Jun 2026, 10:49
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Hi yaswanth9215,

Great question, and you're actually one substitution away from C. Let me point to the exact spot.

You wrote the combined expression as (1.15F + 0.9L) / (10L + L). Notice what you already did in the denominator: you replaced the old total F + L with 10L + L, using S2's fact that F = 10L. That's correct.

The fix is to be consistent - use F = 10L in the numerator too. That F inside 1.15F is the same fixed cost S2 is talking about. S2 says that before the March changes, fixed = 10 x line, i.e. F = 10L. S1 then scales that same F up by 15%, giving new fixed = 1.15F. There aren't two different F's floating around - it's one F, and S2 pins it to L.

So substitute everywhere F appears:

- New fixed = 1.15 x (10L) = 11.5L
- New line = 0.9L
- New total = 12.4L, old total = 11L
- Percent change = 1.4 / 11 = 12.7% increase

The whole thing collapses to a number because the L cancels - once both costs are written in terms of L, the unknown disappears. That's the unique value, so it's C, not E.

Quick sanity check with real numbers - say L = 1, so F = 10:

- Old total = 10 + 1 = 11
- New fixed = 1.15 x 10 = 11.5; new line = 0.9
- New total = 12.4 - change = 1.4/11 = 12.7%

Try L = 5, so F = 50: old = 55, new = 57.5 + 4.5 = 62, change = 7/55 = 12.7%. Same answer every time - that's what makes the combination sufficient.

The takeaway: when one statement gives you a ratio and another gives you a percent change on the same quantity, you can chain them - just substitute the ratio in every place that variable appears.

Answer: C

yaswanth9215
S2 says " Before the changes in March, the fixed cost of manufacturing product P was 10 times the line cost of manufacturing product P". How are we assuming this relationship of F=10L in March? Shouldn't it be (1.15*F +0.9L)/(10L+L) so E?

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The total manufacturing cost of product P is equal to the sum of produ 16 Jun 2026, 21:16
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Thanks for the detailed explanation! Very clear now.
egmat
Hi yaswanth9215,

Great question, and you're actually one substitution away from C. Let me point to the exact spot.

You wrote the combined expression as (1.15F + 0.9L) / (10L + L). Notice what you already did in the denominator: you replaced the old total F + L with 10L + L, using S2's fact that F = 10L. That's correct.

The fix is to be consistent - use F = 10L in the numerator too. That F inside 1.15F is the same fixed cost S2 is talking about. S2 says that before the March changes, fixed = 10 x line, i.e. F = 10L. S1 then scales that same F up by 15%, giving new fixed = 1.15F. There aren't two different F's floating around - it's one F, and S2 pins it to L.

So substitute everywhere F appears:

- New fixed = 1.15 x (10L) = 11.5L
- New line = 0.9L
- New total = 12.4L, old total = 11L
- Percent change = 1.4 / 11 = 12.7% increase

The whole thing collapses to a number because the L cancels - once both costs are written in terms of L, the unknown disappears. That's the unique value, so it's C, not E.

Quick sanity check with real numbers - say L = 1, so F = 10:

- Old total = 10 + 1 = 11
- New fixed = 1.15 x 10 = 11.5; new line = 0.9
- New total = 12.4 - change = 1.4/11 = 12.7%

Try L = 5, so F = 50: old = 55, new = 57.5 + 4.5 = 62, change = 7/55 = 12.7%. Same answer every time - that's what makes the combination sufficient.

The takeaway: when one statement gives you a ratio and another gives you a percent change on the same quantity, you can chain them - just substitute the ratio in every place that variable appears.

Answer: C


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