Question

Mary's earnings vary directly with the number of hours she works. Suppose that she worked 9 hours yesterday and earned $99. If she earned $88 today, how many hours did she work today?

Answer 1

Mary worked 8 hours today.

Step-by-step explanation:

To determine how many hours Mary worked today, we can use the concept of direct variation. Direct variation is a relationship between two variables in which one variable is a constant multiple of the other. In this case, Mary's earnings and the number of hours she works have a direct variation relationship.

Let's use a proportion to solve the problem:

9 hours / $99 = x hours / $88

Cross-multiplying gives us:

9 * $88 = $99 * x

Simplifying, we get:

$792 = $99x

Dividing both sides by $99, we find that x = 792/99 = 8

Therefore, Mary worked 8 hours today.