Capacity of tap B is 80% more than that of A. If both the

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Capacity of tap B is 80% more than that of A. If both the taps are opened simultaneously, they take 45 h to fill the tank. How long will B take to fill the tank alone?

1. 72 h
2. 48 h
3. 66 h
4. 70 h

Correct Option: D

Let time taken by B to fill the tank = T h.
∴ Time taken by A to fill the tank = T + (T x 80)/100 = 9T/5 h

According to the formula,
Time taken by both the taps to fill the tank = ab /(a + b)
⇒ 45 = (T x 9T/5)/(T + 9T/5)
⇒ 45 x 14T/5 = 9T²/5
∴ T = 45 x 14/9 = 70 h