Question

Three small pumps and a large pump are filling a tank. Each of the three small pump works at 2/3 the rate of the large pump. If all four pumps work at the same time, they should fill the tank in what fraction of the time that it would have taken the large pump alone?

2/3
1/3
4/7
3/4

Answer 1

Answer:

♠ The correct option is B

Step-by-step explanation:

Since, each of the three small pump works at 2/3 the rate of the large pump.

Work by three small pumps = Work by two large pumps

All 4 pumps = Three small pumps + One large pump = Three large pumps

♦ All 4 pumps / 1 large pump = 1/3

Answer 2

Question :---- we have to find if Ll four pumps were opened. how much fraction of time they will take to work large pipe alone ....

solution :------

it is given that ,

3 small pipes work = 2/3 of the rate of large pipe ..

so,

3S/L = 2/3

S/L = 2/9

S:L = 2:9 (efficiency ratio)

now let, total tank capacity = 18 litre ,

Larger pipe will take = 18/9 = 2 min

3small + 1 larger will take = 18/(2+3*9) = 18/15 = 6/5 min ..

required fraction = 6/5 * 1/2 = 3/5 (Ans)

none of these options is correct answer .....