CPM Homework Help : INT1 Problem 7-82

Apollo and Zeus are Great Danes and are both on diets. Apollo, is still a puppy and needs to gain weight. He currently weighs $75$ kg and is gaining $2$ kg per month. Zeus is an older dog who needs to lose weight. He currently weighs $130$ kg and is losing $3$ kg per month. In how many months will they weigh the same? Does your solution make sense in the context of this problem?

Hint:

Use a system of equations ( $2$ equations), where
$x =$ number of months and $y =$ weight in kg.

More help:

When writing the equations use slope-intercept form
( $y = mx + b$ ). Where $m$ is the rate of change and $b$ is the starting weight.

Step 1:

Equation for Apollo is $y = 2x + 75$ .
Equation for Zeus is $y = -3x +120$ .

Step 2:

Use the equal values method to solve the system.
So $2x + 75 = -3x + 120$ . Solve for $x$ .

Answer:

$x = 11$ months