Question

20 pumps can empty a reservoir in 12 hours. In how many hours can 45 such pumps do the same work?​

Answer 1

let no. of hours taken by 45 pumps be x

first case,

no. of pumps = 20

no. of hours = 12

second case,

no. of pumps = 45

no. of hours = x

hence, direct variation as less pumps in less time

20/12=45/x

20×x=12×45

20x = 540

x=540/20

x=27

Answer 2

Answer:

20 pump = 12 hours

45 pumps = X

X = 12*20/45

X = 48/9 hours

X = 5.3 hours

Step-by-step explanation:

hope it will help you

$adarsh$