Bunuel wrote:
The Official Guide For GMAT® Quantitative Review, 2ND EditionLast year, if Elena spent a total of $720 on newspapers, magazines, and books, what amount did she spend on newspapers?
(1) Last year, the amount that Elena spent on magazines was 80 percent of the amount that she spent on books.
(2) Last year, the amount that Elena spent on newspapers was 60 percent of the total amount that she spent on magazines and books.
Solution:
Question Stem Analysis:
We need to determine the amount of money Elena spent on newspapers given that she spent a total of $720 on newspapers, magazines, and books. We can let n, m, and b be the amounts (in dollars) she spent on newspapers, magazines, and books, respectively. Therefore, we need to determine the value of n, given that n + m + b = 720.
Statement One Alone:We are given that m = 0.8b. Substituting this in the equation in the stem analysis, we have:
n + 0.8b + b = 720
n + 1.8b = 720
We can’t determine the value of n since we don’t know the value of b. Statement one alone is not sufficient.
Statement Two Alone:We are given that n = 0.6(m + b). Substituting this in the equation in the stem analysis, we have:
0.6(m + b) + m + b = 720
1.6(m + b) = 720
m + b = 450
Since n = 0.6(m + b), n = 0.6(450) = 270. Statement two alone is sufficient.
Answer: B