Problem Solving

talaangoshtari wrote:Two stores usually charge the same regular price for identical jars of peanut butter. This week, Store A is offering the jars of peanut butter for 10% less than regular price, and Store B is offering 6 jars of peanut butter for the regular price of 5. If 6 jars of peanut butter cost a total of $1.18 less at Store B than at Store A this week, what is the regular price of a jar of peanut butter?

A. $2.15
B. $2.95
C. $3.75
D. $4.05
E. $4.65

Store B is offering 6 jars of peanut butter for the regular price of 5
So, we can say that the price of each jar is reduced by 1/6
1/6 ≈ 17% (close enough anyway)

Store A is offering a 10% reduction.

The DIFFERENCE in discounts = 17% - 10% = 7%

6 JARS of peanut butter cost a total of $1.18 less at Store B than at Store A this week
So, 1 JAR of peanut butter costs approximately $0.20 less at Store B than at Store A

So, that 7% difference accounts for the $0.20 price difference.
In other words, 7% of the price for 1 JAR of peanut butter = $0.20
So, (7/100)(price of 1 jar) = 0.20
Solve to get: price of 1 jar = (0.20)(100/7) = 20/7 = slightly less than 3

Answer: B

Cheers,
Brent

Hi talaangoshtari,

This question can be solved algebraically. Since the question has just one variable, we can write everything in terms of that one variable.

X = the regular price of a jar of peanut butter

Based on the information in the prompt, 6 jars of peanut butter would cost:

(6)(.9)(X) = 5.4X at Store A

(5)(X) = 5X at Store B

We're told that those 6 jars cost $1.18 less at store B, so we can combine all of this information into one big equation:

5.4X - 1.18 = 5X

Then do a few algebra steps to simplify:

.4X = 1.18
4X = 11.8

From this, you can see that X must be a little less than $3 (if you wanted to do a few more math steps, then you'd get 2.95 exactly).

Final Answer: B

GMAT assassins aren't born, they're made,
Rich