Question

4 Challenge Between 10 P.M. and 7:20 A.M., the water level in a swimming pool decreased by in. 4/15 Assuming that the water level decreased at a constant rate, how much did the water level drop each hour? The water level decreased by in. each hour. (Simplify your answer. Type an integer, proper fraction, or mixed number.)

Answer 1

The water level decreased by 1/35 inches in each hour

The first thing we will need to do here is to find the number of hours between 10 P.M and 7.20 A.M

That will be;

10 pm to 8 am is 10 hours

But we are stopping at 7.20 am , that is 40 minutes left to complete 10 hours

Thus, we have 9 hours 20 minutes

Let us write 20 minutes as a fraction.

Kindly note that 60 minutes is 1 hour

So 20 minutes is 20/60 = 1/3 hour

So total time is 9 + 1/3 = 28/3 hours

The rate of decrease is 4/15 inches per hour

So we have;

If 4/15 inches decreased in 28/3 hours

Then x inches decrease in 1 hour

Thus;

4/15 * 1 = 28/3 * x

4/15 = 28x/3

4 * 3 = 28x * 15

12 = 420x

x = 12/420

x = 1/35 inches