Question 258985
Jim can fill a pool carrying buckets of water in 30 minutes.
 Sue can do the same job in 45 minutes.
 Tony can do the same job in 1 ½ hours.
 How quickly can all three fill the pool together?
:
Let t = time required all working together
:
Change 1.5 hrs to 90 min
:
Let the completed job = 1 (full pool)
:
Each will do a fraction of the job, the three fractions add up to 1
:
{{{t/30}}} + {{{t/45}}} + {{{t/90}}} = 1
Multiply equation by 90 to get rid of the denominators. results:
3t + 2t + t = 90
6t = 90
t = {{{90/6}}}
t = 15 min all working together
:
:
Check solution on a calc
15/30 + 15/45 + 15/90
.5 + .333 + .167 = 1