AAPL wrote:Magoosh
Mark has fewer than 9 coins. Each coin is either a quarter (worth $0.25) or a dime (worth $0.10). How many dimes does Mark have?
1) The total value of Mark's coins is $1.70.
2) Mark has three times as many quarters as he has dimes.
Statement 1:
To MINIMIZE the number of coins so that a sum of 170 cents is yielded by at most 8 coins, we must MAXIMIZE the number of quarters.
Since 7*25 = 175 cents, the number of quarters must be less than 7.
170 cents will be yielded by 6 quarters (totaling 150 cents) and 2 dimes (totaling 20 cents), for a total of 8 coins and 170 cents.
Using fewer quarters will increase the number of coins beyond 8, violating the condition that Mark has fewer than 9 coins.
Implication:
No other combination of quarters and dimes is possible.
Thus, the number of dimes = 2.
SUFFICIENT.
Statement 2:
Case 1: 1 dime and 3 quarters, for a total of 4 coins
Case 2: 2 dimes and 6 quarters, for a total of 8 coins
Since the number of dimes can be different values, INSUFFICIENT.
The correct answer is
A.
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