A tank has three taps a, b and c. If a and b is open, it can fill the tank in 12 hours, If b and c is open it can fill the tank in 15 hours and if a and c is open it can fill the tank in 20 hours. If only tap a is open in how much time it will fill the entire empty tank alone.
A tank has three taps a, b and c. If a and b is open, it can fill the tank in 12 hours, If b and c is open it can fill the tank in 15 hours and if a and c is open it can fill the tank in 20 hours. If only tap a is open in how much time it will fill the entire empty tank alone. Correct Answer 30 hours
Given:
a and b can fill the tank in 12 hrs
b and c can fill the tank in 15 hrs
a and c can fill the tank in 20 hrs
Calculation:
let capacity of the tank be 60p
the efficiency of a + b = 60p / 12 = 5p ----1
the efficiency of b + c = 60p / 15 = 4p ----2
the efficiency of a + c = 60p / 20 = 3p ----3
adding equation 1,2 and 3
we get, 2a + 2b + 2c = 12p
a + b + c = 6p
so, efficiency of a = 6p - 4p = 2p
Time required to fill the tank by tap a = 60p/2p
⇒ 30 hours
∴ Tap a can fill it in 30 hours