the water type a text 7 minutes more than water tabby for filling up a tank with water the time it takes 16 minutes more than the time taken by the both the taps together to fill the tank find the time it's tab alone will take a fill
in the tank
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Let Tap B takes x mins
Tap B takes x + 7 mins
Tap B takes x mins
⇒ 1 min = 1/x of the tank filled
Tap A takes (x + 7) mins
⇒ 1 min = 1/(x + 7) of the tank filled
Together:
1 min = 1/x + 1/(x + 7)
1 min = [ x + 7 + x] /x(x + 7)
1 min = (2x + 7) /x(x + 7) of the tank
Total time needed to fill the tank together:
mins needed = x(x + 7)/(2x + 7)
The tap A takes 16 minutes more than the time taken by both the taps together to fill the tank:
Tap A = Tap A and Tap B + 16 mins
(x + 7) = x(x + 7)/(2x + 7) + 16
x + 7 - 16 = x(x + 7)/(2x + 7)
x - 9 = x(x + 7)/(2x + 7)
x(x + 7) = (x - 9)(2x + 7)
x² + 7x = 2x² + 7x - 18x - 63
x² - 18x - 63 = 0
(x - 21)(x + 3) = 0
x = 21 or x = - 3 (rejected, time cannot be negative)
Find the time needed:
Tap B = x = 21 mins
Tap A = x + 7 = 21 + 7 = 28 mins
Answer: Tap A takes 28 mins and Tap B takes 21 mins
Tap B takes x + 7 mins
Tap B takes x mins
⇒ 1 min = 1/x of the tank filled
Tap A takes (x + 7) mins
⇒ 1 min = 1/(x + 7) of the tank filled
Together:
1 min = 1/x + 1/(x + 7)
1 min = [ x + 7 + x] /x(x + 7)
1 min = (2x + 7) /x(x + 7) of the tank
Total time needed to fill the tank together:
mins needed = x(x + 7)/(2x + 7)
The tap A takes 16 minutes more than the time taken by both the taps together to fill the tank:
Tap A = Tap A and Tap B + 16 mins
(x + 7) = x(x + 7)/(2x + 7) + 16
x + 7 - 16 = x(x + 7)/(2x + 7)
x - 9 = x(x + 7)/(2x + 7)
x(x + 7) = (x - 9)(2x + 7)
x² + 7x = 2x² + 7x - 18x - 63
x² - 18x - 63 = 0
(x - 21)(x + 3) = 0
x = 21 or x = - 3 (rejected, time cannot be negative)
Find the time needed:
Tap B = x = 21 mins
Tap A = x + 7 = 21 + 7 = 28 mins
Answer: Tap A takes 28 mins and Tap B takes 21 mins
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