2005 AMC 12B Problem 4

Problem 4 of 25EasierAlgebra

At the beginning of the school year, Lisa’s goal was to earn an A on at least

80\%

of her

50

quizzes for the year. She earned an A on

22

of the first

30

quizzes. If she is to achieve her goal, on at most how many of the remaining quizzes can she earn a grade lower than an A?

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Solution

Lisa needs an A on at least

0.8 \cdot 50 = 40

quizzes. She has

22

already, so she needs

40 - 22 = 18

more of the remaining

20

quizzes. She can earn a lower grade on at most

20 - 18 = 2

of them. Thus, the correct answer is B.