Final answer:
Oscar needs to babysit for 3 hours to earn a total of $45, as he makes $15 per hour. This is determined by dividing his total earning goal by his hourly rate.
Step-by-step explanation:
Oscar's situation involves a simple linear relationship between the hours he babysits and the total earnings he accumulates. To determine how many hours it will take for Oscar to earn a total of $45, we use the concept of division, which is part of basic algebra in mathematics. Given that Oscar earns $15 for each hour of babysitting, we can set up an equation to illustrate the relationship between his earnings per hour and the total he wants to earn. We represent the unknown number of hours by the variable, let's call it x. The equation would be:
15 * x = 45.
To find x, we divide both sides of the equation by 15, leading to:
x = 45 / 15.
Dividing 45 by 15 yields 3. Therefore, it would take Oscar 3 hours of babysitting to earn a total of $45. This mathematical operation is a straightforward example of using division to solve for a variable in an equation, which is a common problem in middle school mathematics.