The graph shows the number of paintballs a machine launches, y, in x seconds.

which expression can be used to calculate the rate per second at which the machine launches the balls?

a) 80/4
b) 20/4
c) 4/80
d) 4/20

B) 20/4

Step-by-step explanation:

Required rate =

From the graph, it is evident that (4, 20), (8, 40), (12, 60) and (16, 80) are points.

This means that

20 balls launched in 4 seconds and the rate = 20/4

40 balls launched in 8 seconds and the rate = 40/8 = 20/4

60 balls launched in 12 seconds and the rate = 60/12 = 20/4

80 balls launched in 16 seconds and the rate = 80/16 = 20/4

Hence, the rate per second at which the machine launches the balls is 20/4 and the correct option is (B).

answer:      

step-by-step explanation: