If 12 pumps can empty a reservoir in 20 hours, then time required by 45 such pumps to empty the same reservoir is ______ hours
Solution:
Pumps Time taken to empty
12 20 hours
45 x = ?
More the pumps the faster will be the rate emptying the reservoir. Therefore inverse proportionality is established here.
x = 20 × 12/45
x = 4 × 12/9
x = 4 × 4/3
x = 16/3 or 5 1/3 hours
✦ Try This: If 6 pumps can empty a reservoir in 15 hours, then time required by 30 such pumps to empty the same reservoir is ______ hours.
Pumps Time taken to empty
6 15 hours
30 x = ?
More the pumps, the faster the rate of emptying the reservoir. Therefore:
x = 15 × 6/30
x = 15 × 1/5
x = 3 hours
☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 13
NCERT Exemplar Class 8 Maths Chapter 10 Problem 25
If 12 pumps can empty a reservoir in 20 hours, then time required by 45 such pumps to empty the same reservoir is ______ hours
Summary:
If 12 pumps can empty a reservoir in 20 hours, then time required by 45 such pumps to empty the same reservoir is 5 1/3 hours
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