Question

Two pipes can fill a tank in 25 and 30 minutes
respectively and a waste pipe can empty 5
gallons per minute. All the three pipes
working together can fill the tank in 15
minutes. Find the number of gallons filled
when all the pipes are opened for 15 minutes.
O
92
O
85
O
60
O
90​

Answer 1

Answer:

750 gallons

Step-by-step explanation:

Let, the number of gallons filled  when all the pipes are opened for 15 minutes is x gallon.

So, tank contains x gallons

For first pipe ,

In 25 minutes it fills x gallons

►In 15 minutes it fills $\frac{x\times 15}{25} = 0.6x$ gallons

For second pipe ,

In 30 minutes it fills x gallons

►In 15 minutes it fills $\frac{x\times 15}{30} = 0.5x$ gallons

For third pipe ,

In 1 minute it empties 5 gallon

►In 15 minutes it empties (15×5)=75 gallons

According to question,

0.6x+0.5x-75 = x

►1.1x-x = 75

►0.1x = 75

► x = 750