6. Two water taps together can fill a tank in 9 hours. The tap of larger diameter takes 10
hours less than the smaller one to fill the tank separately. Find the time in which each tap
can separately fill the tank.
Answers
Let the time taken by the smaller tap to fill the tank = x hours
time taken by larger tap = x - 9
In 1 hour, the smaller tap will fill 1/x of tank
In 1 hour, the larger tap will fill 1/(x-9) of tank.
In 1 hour both the tank will the tank = ⅙
In 1 hour both the tank will fill the tank= 1/x + 1/x-9
⅙ = (x-9)+ (x)/(x) (x-9)
⅙ = 2x-9/x²-9x
6(2x-9) = x²-9x
12x-54= x²-9x
x²- 9x-22x +54= 0
x²- 21x+54= 0
x²-18x-3x +54=0
x(x-18)-3(x-18)=0
(x-18) (x-3)=0
x= 18, x=3
We take x= 18
Smaller tap(x)= 18 h
Larger tap (x-9)=18-9= 9h
Hence, the time taken by the smaller tap to fill the tank = 18 hrs & the time taken by the larger tap to fill the tank = 9 h
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Hope this will help you.
Let the time taken by the smaller tap to fill the tank = x hours
time taken by larger tap = x - 9
In 1 hour, the smaller tap will fill 1/x of tank
In 1 hour, the larger tap will fill 1/(x-9) of tank.
In 1 hour both the tank will the tank = ⅙
In 1 hour both the tank will fill the tank= 1/x + 1/x-9
⅙ = (x-9)+ (x)/(x) (x-9)
⅙ = 2x-9/x²-9x
6(2x-9) = x²-9x
12x-54= x²-9x
x²- 9x-22x +54= 0
x²- 21x+54= 0
x²-18x-3x +54=0
x(x-18)-3(x-18)=0
(x-18) (x-3)=0
x= 18, x=3
We take x= 18
Smaller tap(x)= 18 h
Larger tap (x-9)=18-9= 9h
Hence, the time taken by the smaller tap to fill the tank = 18 hrs & the time taken by the larger tap to fill the tank = 9 h