2011 AMC 10B Problem 2

Question

Josanna’s test scores to date are

90,

80,

70,

60,

and

85.

Her goal is to raise her test average at least

3

points with her next test. What is the minimum test score she would need to accomplish this goal?

80

82

85

90

95

Find the current total score and target average

The sixth score must bring the total to

6\cdot80

Her current average is

\dfrac{90+80+70+60+85}5 = 77,

and the sum of her scores is

385.

The desired average is then

80,

so the sum of scores required is

80\cdot 6.

Therefore, the answer is

80\cdot 6-385 = 95.

Thus, the correct answer is E .

Problem 2 in other years