Question

Malia did push-ups and pull-ups in her physical education class. She did 24 push-ups and pull-ups combined, with each push-up taking her 2 seconds and each pull-up taking her 4 seconds. If she spent a total of 68 seconds doing the push-ups and pull-ups, how many pull-ups did she do?

2
4
10
14

Answer 1

Its ten

Explanation:

I just took the exam review and got it right

Answer 2

C. 10

Explanation:

Let x and y represent push-ups and pull-ups, respectively.

x + y = 24 . . . . . . combined total of push/pull-ups

2x +4y = 68 . . . . time required for the exercise

We can divide the second equation by 2 and subtract the first:

(1/2)(2x +4y) -(x +y) = (1/2)(68) -(24)

x +2y -x -y = 34 -24 . . . . . eliminate parentheses

y = 10 . . . . . . . . . simplify

Malia did 10 pull-ups.

__

She did 14 push-ups.