Word problem help

Question

A bath tub is in the shape of a rectangular prism. Its dimensions are 5 feet by 3 feet by 18 inches. The bathtub is three-fourths full of water and drains at a rate of 1 cubic foot per minute. About how long does it take for all the water to drain?

Answer 1

The volume of the tub is 5 ft  * 3 ft * 1.5 ft  = 22.5 ft^3

 

Three-fourths full makes the amount  (3/4)(22.5 ft^3) = 16.875 ft^3

 

Draining at 1 ft^3 / min, it takes almost 17 minutes  (16 7/8).

 

Answer 2

The volume of the tub is 5 · 3 · 18 ft³, or 270 ft³.

It is three-fourths full so the volume of the water is 3/4(270) ft³, or 202.5 ft³

Draining at 1 ft³ / min, it would take 202.5 minutes.