Jim can fill a pool in 30 min. sue can do it 45 min and tony can do it in 90 how quickly can all 3 do it together?

30 + 45 + 90 = 165 divided by 3 (jim,sue,tony all doing it together) = 55min

Imagine the pool holds 90 "units" of water.

Jim is filling 3 units per minute, Sue is filling 2 units per minute, and Tony is filling 1 unit per minute.

Together, they can fill 3+2+1 = 6 units per minute.

\frac{90}{6} = 15\ minutes

Cool on how capuchin reasoned it out. But here is how one would normally set it up to solve algebraically.

\frac{1}{30}+\frac{1}{45}+\frac{1}{90}=\frac{1}{t}

Solve for t. Which should be easy. Just add the fractions on the left side.

Also, another way to set it up is to note that they are completing one whole job.

\frac{t}{30}+\frac{t}{45}+\frac{t}{90}=1

Solve for t.

Oops! Sorry! Guess I wasn't supposed to be averaging out the time... soooo sorry!