2007 AMC 10A Problem 5

Below is the professionally curated solution for Problem 5 of the 2007 AMC 10A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2007 AMC 10A solutions, or check the answer key.

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Concepts:system of equationsmoney

Difficulty rating: 1020

5.

A school store sells 77 pencils and 88 notebooks for $4.15.\$4.15. It also sells 55 pencils and 33 notebooks for $1.77.\$1.77. How much do 1616 pencils and 1010 notebooks cost?

$4.76\$4.76

$5.84\$5.84

$6.00\$6.00

$6.16\$6.16

$6.32\$6.32

Solution:

Let pp and nn be the prices in cents of a pencil and a notebook. Then 7p+8n=415 7p + 8n = 415 5p+3n=177. 5p + 3n = 177.

Solving this system gives p=9p = 9 and n=44.n = 44.

So 1616 pencils and 1010 notebooks cost 16(9)+10(44)=58416(9) + 10(44) = 584 cents, or $5.84.\$5.84.

Thus, the correct answer is B.

Problem 5 in Other Years