Final answer:
To find out how long it will take Roscoe to save $112.50, we can set up a proportion using the given information. The solution is 9 months.
Step-by-step explanation:
To find out how long it will take Roscoe to save $112.50, we can set up a proportion using the given information. We know that Roscoe saves $50 in 4 months. So, the ratio of the amount saved to the time it takes is $50/4 months. We can set up a proportion with the unknown time and amount: $112.50/x months = $50/4 months.
To solve the proportion, we cross-multiply and solve for x:
$112.50 * 4 months = $50 * x months
$450 = $50 * x months
Dividing both sides of the equation by $50, we get:
x months = $450/$50
x months = 9 months.