SOLUTION: How long will it take to fill a reservoir with intake pipes A and B.If the reservoir can be filled by A alone in 5 days and B alone in 3 days?

Question 535966: How long will it take to fill a reservoir with intake pipes A and B.If the reservoir can be filled by A alone in 5 days and B alone in 3 days?

Found 2 solutions by oberobic, richwmiller:
Answer by oberobic(2304) (Show Source): You can put this solution on YOUR website!
Pipe A can do it in 5 days, so it does 1/5 per day.
Pipe B can do it in 3 days, so it does 1/3 per day.
x = number of days working together.
.
(1/5+1/3)*x = 1 full reservoir
.
(3/15 + 5/15)*x = 1
.
8/15 * x = 1
.
8x = 15
.
x = 15/8 = 1 7/8 days to fill the reservoir working together.
.
To check, determine how much of the job each can do in 15/8 days.
1/5*15/8 = 3/8
1/3*15/8 = 5/8
3/8 + 5/8 = 1
Correct.
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
n/5+n/3=1
3n+5n=15
8n=15
n=1 7/8 days
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