Bunuel wrote:
Two hoses are pouring water into an empty pool. Hose 1 alone would fill up the pool in 6 hours. Hose 2 alone would fill up the pool in 4 hours. How long would it take for both hoses to fill up two-thirds of the pool?
A. 5/12 hours
B. 5/8 hours
C. 8/5 hours
D. 12/7 hours
E. 12/5 hours
Kudos for a correct solution.
METHOD-1Hose 1 would fill the pool alone in 6 hours
i.e. 1 Hour work of Hose 1 = 1/6
Hose 2 would fill the pool alone in 4 hours
i.e. 1 Hour work of Hose 2 = 1/4
i.e. 1 Hour work of Hose1 and Hose2 together = (1/6)+(1/4) = (5/12)
i.e. (5/12) work can be finished by Hose1 and Hose2 together in 1 hour
i.e. (2/3) work can be finished by Hose1 and Hose2 together in 1*(12/5)*(2/3) = 8/5 hourAnswer: Option CMETHOD-2Assume the Capacity of Tank that is Divisible by 4 and 6
Let, Capacity of Tank = 12 Units
i.e. Amount of water intake from Hose 1 in 1 hour = 12/6 = 2 Units
i.e. Amount of water intake from Hose 2 in 1 hour = 12/4 = 3 Units
i.e. Amount of water intake from Hose 1&2 together in 1 hour = 2 + 3 = 5 Units
2/3 of tank capacity = (2/3)*12 = 8 Units
Time taken by Hose 1&2 together to fill 5 units = 1 hour
i.e. Time taken by Hose 1&2 together to fill 8 units = 8/5 hour
Answer: Option C
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