Pls help !!

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Pls help !!

by candygal79 » Wed Mar 26, 2014 8:32 pm
. Jim is able to sell a hand-carved statue for $670 which was a 35% profit over his cost. How much did the statue originally cost him?

A. $496.30
B. $512.40
C. $555.40
D. $574.90
E. $588.20

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by gmat_chanakya » Wed Mar 26, 2014 8:57 pm
Answer is A.

35% profit means 1.35 times original cost

this means 1.35x = 670
and therefore x = 496.30

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by [email protected] » Thu Mar 27, 2014 12:08 am
Hi candygal79,

This question can also be solved by TESTing THE ANSWERS.

One of those 5 answers, when increased by 35% will equal $670

Let's say that you started with answer D and did a rough estimate...

$574 x 10% = about $57
$574 x 30% = about $171
$574 + $171 = $745 which is TOO HIGH

Now let's try answer B and do a rough estimate...

$512 x 10% = about $51
$512 x 30% = about $153
$512 x 35% = about $178
$512 + $178 = $690 which is TOO HIGH

The final answer MUST be lower than answer B

Final Answer: A

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Rich
Contact Rich at [email protected]
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by Brent@GMATPrepNow » Thu Mar 27, 2014 8:07 am
I just wanted to point out that all students should know Rich's technique for finding x percent of y.
It's based on the fact that it's incredibly easy to find 10% of any value. For example, 10% of 39 is 3.9, and 10% of 4210 is 421.

Also notice that, if we can find 10% of a number, it's just as easy to find 5% of that same number.
For example, since 10% of 42 is 4.2, we know that 5% of 42 will be 2.1 (i.e., HALF of 4.2)
Likewise, since 10% of 680 is 68, we know that 5% of 680 will be 34 (i.e., HALF of 68)

So, to find 15% of x, we'll find 10% of x, and we'll find 5% of x
For example, let's find 15% of 180.
10% of 180 = 18
So, 5% of 180 = 9
This means that 15% of 180 = 18 + 9 = 27

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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