Question

Peter's class launches a helium balloon for an experiment. The coordinate grid shows the height of the balloon as it rises in height. At what rate does the balloon rise in height?

A. 40 feet per second
B. 100 feet per second
C. 30 feet per second
D. 50 feet per second​

Answer 1

C. 30 feet per second

Explanation:

Looking at the graph, after 5 seconds, the balloon reaches 150 feet

at 10 seconds, it reaches 300 feet

Slope m = (y2-y1)/(x2-x1) = (300 - 150)/(10 - 5) = 150/5 = 30

y = mx + b

300 = 30(10) + b

300 = 300 + b

b = 0

then y = 30x