Question

The graph shows the height of a tire's air valve y, in inches, above or below the center of the tire, for a given number of seconds, x.

How many revolutions does the tire make in 2 minutes?

A. 180
B. 40
C. 20
D. 10​

Answer 1

b

Explanation:

b

Answer 2

B. 40

Explanation:

According to the graph, the tire completes a revolution after 3 seconds.

Bascically, the rate of revolution is 3 seconds per revolution.

We can use the rule of three to find the number of revolutions made in 2 minutes, which is 120 seconds.

`120sec(1rev)/(3sec) =40rev`

Therefore, the tire makes 40 revolutions in 2 minutes.

Remember that the distances between two extreme points represents the time of one revolution. Observe that the tire began at 0 seconds and completed a revolution at x = 3, that's the period of the tire.