sandy wrote:

A container is \(\frac{4}{5}\) full. After 3 liters of its contents are poured out, the container is \(\frac{3}{4}\) full. How many liters would need to be poured back in to refill the container?

Let C = capacity of the container

We can write: (original volume of liquid) - 3 liters = (new volume of liquid)

Rewrite as: (4/5 of C) - 3 = (3/4 of C)

Or...: 4C/5 - 3 = 3C/4

Rearrange to get: 4C/5 - 3C/4 = 3

Rewrite with common denominators: 16C/20 - 15C/20 = 3

Simplify: C/20 = 3

Solve: C = 60

In other words, the container's capacity is

60 litersIf the container is 3/4 full, then the volume of liquid = 3/4 of

60 liters = 45 liters

So, we must add 15 more liters to fill the container.

Answer:

Cheers,

Brent

_________________

Brent Hanneson – Creator of greenlighttestprep.com

Sign up for our free GRE Question of the Day emails