3 pumps working 8 hours a day, can empty a tank in 2 days. How many hours a day

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Question
3 pumps working 8 hours a day, can empty a tank in 2 days. How many hours a day must 4 pumps work to empty the tank in 1 day?
Options
A. 9
B. 10
C. 11
D. 12

Correct Answer

12

Explanation

Let the required no of working hours per day be x.

More pumps , Less working hours per day (Indirect Proportion)

Less days, More working hours per day (Indirect Proportion)

$\begin{array}{r} \begin{matrix} P u m p s & 4 : 3 \end{matrix} \\ \begin{matrix} D a y s & 1 : 2 \end{matrix} \end{array}\} ? ? 8 : x$

=> (4 * 1 * x) = (3 * 2 * 8)

=> x=12

Chain Rule problems

Search Results

1. 39 persons can repair a road in 12 days, working 5 hours a day. In how many days will 30 persons, working 6 hours a day, complete the work?
Options
A. 10
B. 13
C. 14
D. 15

2. A contractor undertakes to do a piece of work in 40 days. He engages 100 men at the begining and 100 more after 35 days and completes the work in stipulated time. If he had not engaged the additional men, how many days behind schedule would it be finished?
Options
A. 3
B. 5
C. 6
D. 9

3. If 7 spiders make 7 webs in 7 days, then 1 spider will make 1 web in how many days?
Options
A. 1
B. 3
C. 7
D. 14

4. 2 men and 7 boys can do a piece of work in 14 days; 3 men and 8 boys can do the same in 11 days. Then, 8 men and 6 boys can do three times the amount of this work in
Options
A. 18 days
B. 21 days
C. 24 days
D. 30 days

5. If 36 men can do a piece of work in 25 hours, in how mwny hours will15 men do it?
Options
A. 40
B. 50
C. 60
D. 70

6. If 18 bindres bind 900 books in 10 days , How many binders will be required to bind 660 books in 12 days?
Options
A. 22
B. 14
C. 13
D. 11

7. 36 men can complete a piece of work in 18 days. In how many days will 27 men complete the same work ?
Options
A. 24 days
B. 28 days
C. 34 days
D. 35 days

8. If a quarter kg of carrots costs 60 paise, how many paise will 200 gms cost ?
Options
A. 78 paise
B. 48 paise
C. 54 paise
D. 62 paise

9. The sum of 3rd and 15th elements of an arithmetic progression is equal to the sum of 6th, 11th and 13th elements of the same progression. Then which element of the series should necessarily be equal to zero ?
Options
A. 14th element
B. 9th element
C. 12th element
D. 7th element

10. Some persons can do a piece of work in 12 days. Two times the number of such persons will do half of that work in
Options
A. 6 days
B. 12 days
C. 4 days
D. 3 days

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