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One pipe alone will fill a tank in 7 1/2 hours. A second pipe will fit it alone in 10 hours. If the second pipe were open for 8 hours and then closed, how long would the first pipe take to finish filling the tank?

Respuesta :

joseaaronlara

Answer:

The answer to your question is 1.5 hours

Step-by-step explanation:

Data

Pipe 1 fill the tank in 7 1/2 h

Pipe 2 fill the tank in 10 h

time the pipe 2 was opened 8 h

Time to fill the tank = x

Process

1.- Calculate the amount of the tank filled with the second pipe

                10 hours  --------------------- 1  tank filled

                  8 hours  --------------------  x

                   x = 8 x 1 / 10

                   x = 8/10

                   x = 4/5

   The second pipe filled 4/5 of the tank in 8 hours.

2.- Calculate the time the first pipe will fill 1/5 of the tank

7 1/2 = 15/2

              15/2 h ------------------------- 1 tank filled

                 x      -------------------------  1/5

                 x = (1/5)(15/2)/1

                 x = 15/10

                 x = 3/2

                x = 1.5 h                  

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