2013 AMC 10A Problem 9

Below is the professionally curated solution for Problem 9 of the 2013 AMC 10A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2013 AMC 10A solutions, or check the answer key.

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Concepts:percentagelinear equation

Difficulty rating: 1020

9.

In a recent basketball game, Shenille attempted only three-point shots and two-point shots. She was successful on 20%20\% of her three-point shots and 30%30\% of her two-point shots. Shenille attempted 3030 shots. How many points did she score?

1212

1818

2424

3030

3636

Solution:

Let xx be the number of two-point shots and yy be the number of three-point shots.

Then, Shenille scores .3x.3x two-points shots and .2y.2y three-point shots, for a total score of 2.3x+3.2y=.6x+.6y. 2 \cdot .3x + 3 \cdot .2y = .6x + .6y.

We know that x+y=30 x + y = 30 .6(x+y)=18. .6(x + y) = 18.

Thus, B is the correct answer.

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