Question

A mermaid has a terrarium that measures 42 inches × 10 inches × 9 inches. She also has a box

that measures 3 inches × 3 inches × 3 inches. Every minute, the mermaid fills the box with sand
from her backyard and then pours the sand into the terrarium. How many minutes does it take the
mermaid to fill three-quarters of the terrarium with sand?

Answer 1

Answer: It will take her 1 hour and 45 min

Explanation:

Answer 2

105 minutes

Explanation:

The volume of the terrarium is ...

V = LWH

V = (42 in)(10 in)(9 in) = 3780 in³

The volume of a box is ...

V = (3 in)(3 in)(3 in) = 27 in³

Then the number of boxes it takes to fill the terrarium is ...

(3780 in³)/(27 in³/box) = 140 boxes

The mermaid wants to fill it 3/4 full, so only needs 3/4 this number of boxes. That is 105 boxes. At the rate of 1 per minute, ...

it will take 105 minutes to fill 3/4 of the terrarium