Chain Rules - Online Quiz



Following quiz provides Multiple Choice Questions (MCQs) related to Chain Rules. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Questions and Answers

Q 1 - If 21 cows eat as much as 15 buffaloes, how many cows will eat as much as 35 buffaloes?

A - 49

B - 56

C - 45

D - 47

Answer : A

Explanation

15 buffaloes = 21 cows ⇒ 1 buffalo = 21/15 cows = 7/5 cows
⇒35 buffaloes = (35 * 7/5 ) cows = 49 cows.

Q 2 - The Qutab minar casts a shadow 150m long at the same time when the vikes minar casts a shadow 120m long on the ground . If the height of the Vikes minar is 80m, what is the height of the Qutab Minar?

A - 100m

B - 120m

C - 150m

D - 180m

Answer : A

Explanation

Let the height of  the Qutab Minar be x metres.
Longer is the shadow , longer is the object    (Direct)
120 : 150 :: 80 : x ⇒ 120 * x = (150 *80)⇒ x= (150 *80)/120=100m.
Height of Qutab Miinar = 100m.

Q 3 - 20 men complete one ? third of a piece of work in 20 days . How many more men should be employed to finish the rest of the work in 25 more days?

A - 10

B - 12

C - 15

D - 20

Answer : B

Explanation

Work done =1/3  , Remaining work = (1 - 1/3 ) = 2/3
Let number of more men to be employed be x.
More work, More men       (Direct)
More days , less men     (Indirect)
Work 1/3 : 2/3
:: 20 : (20 +x)
Days 25 : 20
1/3 * 25 * ( 20+ x) = 2/3 * 20 *20 ⇒ (20 + x) = 800/25 = 32 ⇒ x = (32-20) = 12.

Q 4 - A does half as much work as B in one- sixth of time. If together they take 10 days to complete the work, how much time shall B alone take to do it ?

A - 70 days

B - 40 days

C - 30 days

D - 20 days

Answer : B

Explanation

Suppose B takes x days to finish the work .
Then , A takes x/6 days to finish half the work .
∴ A takes 2x / 6 = x/3 days to finish the work.
1/x + 3/x = 1/10 ⇒ 4/x = 1/10 ⇒  x= 40.
Hence , B along takes 40 days to finish the work.

Q 5 - 40 men take 8 days to ears Rs 2000. How many men will earn Rs 200 in 2 days?

A - 1

B - 2

C - 3

D - 4

Answer : A

Explanation

Let  the required number of  men  b  x.
Less  earning , less men     (Direct)
Less days , less men      (Direct)
Earning     2000  : 200
:: 40 : x
Days       8 :  2
∴ (2000 * 8 * x ) = (200 * 2 * 40 ) ⇒ x = 200* 2 * 40 / 2000 * 8  = 1 .
Required number of men = 1.

Q 6 - A contractor undertakes to build a wall in 50 days. He employs 50 people for the same . However, after 25 days , he finds that only 40 % of the work is complete , How many more men need to be employed to complete the work in time?

A - 20

B - 25

C - 30

D - 35

Answer : B

Explanation

Work done = 40/100 = 2/5 , Remaining work = ( 1 - 2/5 ) = 3/5.
2/5 work is done in 25 days by 50 people.
3/5 work will be done in 25 days by (50 * 5/ 2 * 3/5) people = 75 people.
Required number of people = ( 75 ? 50 )  = 25.

Q 7 - 8 men working for 9 hours a day complete a piece of work in 20 days . In how many days can 7 men working for 10 hours a day complete the same piece of work?

A - 41/2 days

B - 103/5 days

C - 21 days

D - 144/7 days

Answer : D

Explanation

Let the required number of days be x .
Less men , more days      ( Indirect)
More  working hours, less days      (Indirect)
Men    7: 8
:: 20 : x
Working hrs   10 : 9
∴ ( 7 * 10 * x ) = ( 8 * 9 * 20) ⇒ x = 8 * 9 * 20 / 7 * 10  = 144/7 = 144/7.

Q 8 - In a hospital, there is a consumption of 1350 litres of milk for 70 patients for 30 days. How many patients will consume 1710 litres of milk in 28 days?

A - 59

B - 85

C - 95

D - 105

Answer : C

Explanation

Let the required number of patients be x .
More milk, more patients        (Direct)
Less days , more patients        (Indirect)
Litres   1350:1710
::70 : x 
Days       28 : 30
∴ ( 1350 * 28 * x ) = ( 1710 * 30 * 70) ⇒ x= 1710 * 30 * 70/ ( 1350 * 28 ) = 95 patients.

Q 9 - If 18 pumps can raise 2170 tonnes of water in 10 days , working 7 hours per day , in how many days will 16 pumps rise 1736 tonnes, working 9 hours per day?

A - 9 days

B - 8 days

C - 7 days

D - 6 days

Answer : C

Explanation

Let the required number of days be x.
Less pumps, more days      (Indirect)
Less water, less days        (direct)
More working hrs, less days   (Indirect)
Pumps  16:18
Water Qty.     2170 : 1736          :: 10 :x
Water hrs     9:7
∴ (16 * 2170 * 9 *x ) =   ( 18 * 1736*7 *10)⇒ x=18 * 1736*7 *10/16*2170 * 9 = 7 days .

Q 10 - A contractor employed 30 men to do a piece of work in 38 days. After 25 days he employed 5 men more and the work was finished one day earlier. How many days , he would have been behind , if he had not employed additional men?

A - 1 day

B - 5/4 days

C - 3 days

D - 7/4 days

Answer : A

Explanation

After 25 days , 35 men finish the remaining work in (38 - 25 - 1) = 12 days.
35 men can finish the remaining work in 12 days.
30 men can finish it in (12 * 35) /30  days = 14 days , i.e. 1 day behind.

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