Question

The amount of gallons of water remaining in a swimming pool after x hours is given by the equation,

y = -4,000x + 20,000
How long before the pool is completely drained?
O 1 hour
5 hours
3 hours
6 hours

Answer 1

5 hours.

Explanation:

When it is drained y will be = to zero, so

-4000x + 20000 = 0

-4000x = -20000

x = -20000/ -4000

= 5.

Answer 2

5 hours

Explanation:

The pool will be completely drained when y = 0

0 = -4,000x + 20,000

subtract 20,000 from both sides

-20,000 = -4,000x

divide both sides by -4,000

x = 5

Have a good day!