tricky?

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 117
Joined: Fri Oct 17, 2008 7:41 am

tricky?

by awilhelm » Tue Jan 20, 2009 3:08 pm
A store purchased 20 coats that each cost an equal amount and then sold each of the 20 coats at an equal price. What was the store's gross profit on the 20 coats?

1) If the selling price per coat had been twice as much, the gross profit would've been $2,400.

2) If the selling price per coat had been $2 more, the gross profit would've been $440

OA is B. I had D. What am I missing here? Reasoning below.

2 ->
let x = selling price
20*(x + 2) = $440
20x + 40 = $440
20x = $400
x = $20
This only gives me the selling price, but says nothing about what my costs were, and therefore nothing about my gross profit.
Source: — Problem Solving |

Master | Next Rank: 500 Posts
Posts: 259
Joined: Thu Jan 18, 2007 8:30 pm
Thanked: 16 times

by amitabhprasad » Tue Jan 20, 2009 4:12 pm
Profit = SP-CP
Stmt 1: 20(2*SP-CP) = 2,400
from here we cant get SP-CP
so insufficient
Stmt 2: 20(SP+2-CP) = 440
==> SP-CP = 20
sufficient

Master | Next Rank: 500 Posts
Posts: 117
Joined: Fri Oct 17, 2008 7:41 am

by awilhelm » Tue Jan 20, 2009 6:24 pm
Thanks, but why couldn't we manipulate the first statement as follows:

Stmt 1 ->
20(2*(SP-CP)) = 2,400

20/2 * (2*(SP-CP))/2 = 2,400/2

10 * SP-CP = 1,200

SP-CP = 120

???

Master | Next Rank: 500 Posts
Posts: 259
Joined: Thu Jan 18, 2007 8:30 pm
Thanked: 16 times

by amitabhprasad » Tue Jan 20, 2009 6:40 pm
How can you do
2*(SP-CP)....
Statement says 2 times the selling price
not 2 times the profit.

Master | Next Rank: 500 Posts
Posts: 117
Joined: Fri Oct 17, 2008 7:41 am

by awilhelm » Tue Jan 20, 2009 6:53 pm
Right, I see, thanks.