Chapter ISG, Problem 3.3.13P

To determine

To calculate the change in the monthly bill each year.

Answer to Problem 3.3.13P

The change in the monthly bill each year is $5

Explanation of Solution

Given information:

Isabel’s bill this year is $40 this year

Isabel’s bill three year age is $25.

Formula used:

Rate of change,

  $=\frac{ChangeInY}{ChangeInX}$

Calculation:

The difference in year is 3, therefore,

  $ChangeInX=3$

For the change in y,

The change is y is bill this year- bill 3 years ago.

  $ChangeInY=40-25$

On solving,

  $ChangeInY=15$

For the change in monthly bill is, substituting the value,

  $=\frac{15}{3}$

On solving,

  $=5$

Hence, the change in the monthly bill each year is $5