sue can do it in 45 min so he is equal to 30/45 of jim

tony can do it in 90 min so he is equal to 30/90 of jim

So 1+30/45+30/90 of jim have to do the work which is equal to 90/90+60/90+30/90=180/90=2jim

so all three can do the work in half time of jim that is 15 min

this can be solved by deriving the HCF of all three that is once more 15 minute

It doesn’t say how many buckets of water the pool holds, but you can make something up and work it out from there. The answer will be the same no matter what you make up for the pool capacity.

Let’s say it holds 30 buckets.

That means Jim carries 1 bucket /minute

Sue carries 2/3 bucket/minute

Tony carries 1/3 bucket/minute.

For each minute that passes, the 3 of them carry

(1+2/3+1/3=) 2 buckets of water.

The whole pool holds 30 buckets so they are done in

(30/2=) 15 minutes.

Does this make sense? Yes, because the three of them working together should get it done faster than the fastest one working alone.

So the steps are:

1. Make up a capacity for the pool that will make the math easy.

2. Figure out a per-minute rate at which each person works.

3. Add up all the per-minute rates to get a total per-minute rate when they all work simultaneously.

4. Divide the total capacity by the total per-minute rate.

2 minutes ago – Report Abuse

Let’s say it holds 30 buckets.

That means Jim carries 1 bucket /minute

Sue carries 2/3 bucket/minute

Tony carries 1/3 bucket/minute.

For each minute that passes, the 3 of them carry

(1+2/3+1/3=) 2 buckets of water.

The whole pool holds 30 buckets so they are done in

(30/2=) 15 minutes.

Does this make sense? Yes, because the three of them working together should get it done faster than the fastest one working alone.

So the steps are:

1. Make up a capacity for the pool that will make the math easy.

2. Figure out a per-minute rate at which each person works.

3. Add up all the per-minute rates to get a total per-minute rate when they all work simultaneously.

4. Divide the total capacity by the total per-minute rate.

it’s 15 minutes because 1/2 + 1/3 + 1/6 = 3/6 + 2/6 + 1/6 = 1 full pool