2014 AMC 10B Problem 1

Below is the professionally curated solution for Problem 1 of the 2014 AMC 10B, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2014 AMC 10B solutions, or check the answer key.

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Concepts:linear equationmoney

Difficulty rating: 560

1.

Leah has 1313 coins, all of which are pennies and nickels. If she had one more nickel than she has now, then she would have the same number of pennies and nickels. In cents, how much are Leah's coins worth?

33 33

35 35

37 37

39 39

41 41

Solution:

Let the number of pennies be p.p. Then, the number of nickels is 13p13-p and p1,p-1, so 13p=p1.13-p=p-1. This means we have 77 pennies and 66 nickels.

Therefore, the number of cents is 7+65=37.7+6\cdot 5=37.

Thus, the correct answer is C .

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