Gallons in a tank

[money9111]

After 4,000 gallons of water were added to a large water tank that was already filled to 3/4 of its capacity, the tank was then at 4/5 of its capacity. How many gallons of water does the tank hold when filled to capacity?

a. 5,000
b. 6,200
c. 20,000
d. 40,000
e. 80,000

How do you set this up initially?

Sidenote - if someone can tell me how to hide the answer so people can highlight over it... i'll do that when I post questions. I just don't know how to do that right now :-/

[ajith]

After 4,000 gallons of water were added to a large water tank that was already filled to 3/4 of its capacity, the tank was then at 4/5 of its capacity. How many gallons of water does the tank hold when filled to capacity?

a. 5,000
b. 6,200
c. 20,000
d. 40,000
e. 80,000

How do you set this up initially?

Sidenote - if someone can tell me how to hide the answer so people can highlight over it... i'll do that when I post questions. I just don't know how to do that right now :-/

Use spoiler button (right top along with img URL buttons) - That was an easy query

tank was 75% full initially and it was 80% full after pumping in 4000 gallon

So 5% of the tank's capacity is 4000

What is 100% is the question = 4000*100/5 = 80,000

[money9111]

hhhm like this? testing testing 123

[papgust]

Let 'x' be the total capacity of a tank.

Already filled tank is (3/4 * x)

After 4000 gallons were poured in, filled tank is (4/5 * x)

So, (4x/5 - 3x/4) = 4000

16x - 15x = 4000 * 20

x = 80,000.


Note: You can highlight the OA and click button 'Spoiler' to hide the answer.

[money9111]

just in case anyone else was wondering:

OA E even though that wasn't a difficult question

[thephoenix]

3x/4+4000=4x/5

solving x=80000

[money9111]

I guess we need more challenging problems! lol

[sanju09]

After 4,000 gallons of water were added to a large water tank that was already filled to 3/4 of its capacity, the tank was then at 4/5 of its capacity. How many gallons of water does the tank hold when filled to capacity?

a. 5,000
b. 6,200
c. 20,000
d. 40,000
e. 80,000

How do you set this up initially?

Sidenote - if someone can tell me how to hide the answer so people can highlight over it... i'll do that when I post questions. I just don't know how to do that right now :-/

It cannot be more simple problem on fractions than this one, on GMAT.

4/5 - 3/4 = 1/20 of the capacity is 4,000 gallons; therefore total capacity is 20*4,000 gallons = [spoiler]80, 000[/spoiler] gallons.

[spoiler]E[/spoiler]