Two pipes A & B can fill a swimming pool at a consant rate in 60 hours, 40 hours, or 24 hours, depending on whether pipe A alone, pipe B alone, or both pipes are used. If the pool is filled by using pipe B alone for half the time and both pipes for half the time, how many hours does it take to fill the pool?
Now i know sort of how to solve this problem, but the solution explanation throws me off and I get the problem wrong obviously.
usually work problems are sovled by an equation much like the following right?
time/job1 + time/job2 = 1 <--- one being the whole job
so wouldnt this problem be solved like this?:
1/40 (for pipe b) + 1/24 (for both) = X <--- being the time for both combinations to fill the pool
right?
but the solution set says that this is the formula:
.05t/40+.05t/24=1
I dont quite get that problem
okay so the =1 is the whole pool, I get that
obviously .05 isnt the half the time it takes to fill the pool either? That would be .5
so where did the .05t come from?
Work problem I cant seem to solve
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- jayhawk2001
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You almost have it right. So, I'd suggest that you stick with your approach.sev wrote: so wouldnt this problem be solved like this?:
1/40 (for pipe b) + 1/24 (for both) = X <--- being the time for both combinations to fill the pool
right?
x*1/24 + x*1/40 = 1
Solving for x, we get 15
So, time taken = 15 + 15 = 30 hours.