Question

Mr. Garcia asked the members of his health class how many days last week they exercised for at least 30 minutes. The results are summarized in the following bar graph, where the heights of the bars represent the number of students.

What was the mean number of days of exercise last week, rounded to the nearest hundredth, reported by the students in Mr. Garcia's class?

$3.50$

$3.57$

$4.36$

$4.50$

$5.00$

Answer: C

Concepts:mean data and graph interpretation

Difficulty rating: 960

Video solution:

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Written solution:

The bar heights for $1,2,3,4,5,6,7$ days are $1,3,2,6,8,3,2$ , for a total of $25$ students.

The total number of reported exercise days is $\begin{aligned} &1\cdot1+2\cdot3+3\cdot2+4\cdot6\\ &\qquad+5\cdot8+6\cdot3+7\cdot2=109. \end{aligned}$

The mean is $109/25=4.36$ days.

Thus, C is the correct answer.

2018 AMC 8 Problem 8

Answer: C

Difficulty rating: 960

Video solution:

Written solution:

Problem 8 in Other Years