Aquarium Problem

Question: If it took Bob 1 minute to fill his aquarium 1/3 full, how long would it take him to fill it 3/4 full?

I did this problem by doing proportions:

33% = 75%
60 sec. X

I then came up with 33x = 4500 and got the answer as 2 min. 16 sec.

Am I correct?

jramirez23 said:

Question: If it took Bob 1 minute to fill his aquarium 1/3 full, how long would it take him to fill it 3/4 full?

I did this problem by doing proportions:

33% = 75%
60 sec. X

I then came up with 33x = 4500 and got the answer as 2 min. 16 sec.

Am I correct?

Click to expand...

Why not do this?

1 / (1/3) = x / (3/4)

Then solve for x... I would cross-multiply:

1 * (3/4) = (1/3)*x

and take it from there....

jramirez23 said:

Question: If it took Bob 1 minute to fill his aquarium 1/3 full, how long would it take him to fill it 3/4 full?

I did this problem by doing proportions:

33% = 75%
60 sec. X

I then came up with 33x = 4500 and got the answer as 2 min. 16 sec.

Am I correct?

Click to expand...

Sort of - but use fractions instead of decimal (like MrsPi showed) - the actual answer is 2 min 15 sec

Question: If it took Bob 1 minute to fill his aquarium 1/3 full, how long would it take him to fill it 3/4 full?

Or...think it through.

it took 1 minute to fill his aquarium 1/3 full

it took 3 minutes to fill it 3/3 (= 1) (all the way) full.

(divide by 4) it took 3/4 minutes to fill it 1/4 full.

(multiply by 3) it took 3(3/4) = 9/4 minutes to fill it 3(1/4) full.

It took 2 1/4 minutes (2 minutes and 15 seconds) to fill it 3/4 full.

You are off by one second because you used 33% rather than 33 1/3% or 1/3. In other words, put 1/3 in place of 33% in your proportion, then solve.