Question 147

Pipe A can fill a tank of capacity 350 litres in $$3\frac{1}{2}$$ minutes. Pipe B can fill a tank of capacity 780litres in $$8\frac{2}{3}$$ minutes. How long (in min)will it take to fill a tank of capacity 1615 litres, if both pipes are opened together?

Solution

Efficiency = capacity/time

Time taken by pipe A = $$3\frac{1}{2} = \frac{7}{2}$$

Efficiency of pipe A = 350$$ \times \frac{2}{7}$$ = 100

Time taken by pipe B = $$8\frac{2}{3} = \frac{26}{3}$$

Efficiency of pipe B = 780 $$ \times \frac{3}{26}$$ = 90

Efficiency of pipe A and B = 100 + 90 = 190

time taken by both pipes to fill the 1615 liters = 1615/190 = $$8\frac{1}{2}$$

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