Question

Sally's huge dog weighed 145 pounds in 2006 and then weighed 175 pounds in 2018. What was the rate of change in weight? *

3.5 pounds per year
5 pounds per year
7.5 pounds per year
2.5 pounds per year

Answer 1

2.5 pounds per year

Explanation:

In this situation, we're looking at a linear change and a graph, and as such we'll just need to find the slope as in a linear graph that tells us how much the change is between two points and will be our rate here.

1 - Get your variables laid out

Because we're looking for a per year rate, its weight/year and thus because we need to find the change in y over the change in x then:

x = Years

y = Weight

2 - Find the slope

`Slope = m = (rise)/(run) = (change~in~y)/(change~in~x) = (y_2-y_1)/(x_2-x_1) = (175-145)/(2018-2006) = (30)/(12)`

3 - Find the rate of change

Sallys dog gained 30 pounds over 12 years. The rate of change is pounds/year which is 30/12

30/12 = 2.5 pounds per year

Hope this helps :)