Chain Rules - Online Quiz


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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 4/5th of a cistern is filled in 1 minute, how much more time will be required to fill the rest of it?

A - 20 seconds

B - 15 seconds

C - 12 seconds

D - 10 seconds

Answer : B

Explanation

Let the required time be x seconds.
Part filled = 4/5, Remaining part = (1- 4/5 ) = 1/5.
Less  part to be filled , less is the time taken     (direct)
4/5 :1/5 :: 60 : x ⇒ 4/5 * x = (1/5 * 60 ) = 12 ⇒ x= (12 * 5/4 ) = 15.
Required time = 15 seconds.

Q 2 - 3 men or 5 women can finish a piece of work in 12 days. How long will 6 men and 5 women take to finish the work?

A - 4 days

B - 10 days

C - 15 days

D - 20 days

Answer : A

Explanation

3 men = 5 women ⇒ 6 men =10 women
⇒ (6 men +5 women )= 15 women.
Let the required number  of days be x.
More women , less days      (Indirect)
15 : 5 :: 12 :  x ⇒ 15x = (5* 12 ) ⇒ x= (5*12)/15 = 4 days

Q 3 - 8 men can complete a piece of work in 12 days ; 4 women can complete it in 48 days and 10 children can complete the same piece of work in 24 days . In how many days can 10 men , 4 women and 10 children complete the same piece of work?

A - 5 days

B - 15 days

C - 28 days

D - 6 days

Answer : D

Explanation

1 man can complete the work in ( 12 * 8) = 96 days.
1 women can complete the work in ( 48 * 4) = 192 days.
1 child can complete the work in ( 24 * 10) = 240 days.
1 men 1 days work = 1/96, 1 women1 days work = 1/192.
1 child 1 days work = 1/240.
( 10 men + 4 women + 10 children) 1 days work = ( 10/ 96 + 4/192 + 10/240)
= (5/48 + 1 /48 + 1/24) = 8/48 = 1/6.
∴ They will do the work in 6 days.

Q 4 - 8 men can finish a piece of work in 40 days . If 2 more men join with them , then the work will be completed in?

A - 30 days

B - 32 days

C - 36 days

D - 25 days

Answer : B

Explanation

Let  10 men finish it in x days.
More men, less days     (Indirect)
10 : 8 :: 40 : x ⇒ 10x = (8 * 40 ) ⇒ x = (8*40) /10 = 32 days.

Q 5 - Two persons can complete a piece of work in 9 days. How many more persons are needed to complete double the work in 12 days?

A - 1

B - 2

C - 3

D - 4

Answer : A

Explanation

Let the required number of persons be x .
More work, more  persons          (direct)
More  days  , less persons          (Indirect)
Work      1:2
:: 2 : (2+x)
Days    12:9 
 1*12 * ( 2 + x ) = (2 * 9 *2 ) ⇒ ( 2 + x ) = 36/12 = 3 ⇒ x=1.

Q 6 - A contract is to be completed in 46 days and 117 men were set to works , each working 8 hours a day. After 33 days , 7/4 of the work is completed . How many additional men may be employed so that the work may be completed in time , each man now working 9 hours a days?

A - 80

B - 81

C - 82

D - 83

Answer : B

Explanation

Let the required number of men be x.
Work done = 4/7 , Remaining work  = ( 1- 4/7 ) = 3/7.
Less days , more  men           (Indirect)
More hrs/day, less men         (Indirect)
Less work , less men         ( Direct)
Days   13 : 33
Hrs/days    9:8 :: 117 : ( 117 +x)
Work:  4/7  :  3/7
∴ 13 * 9 * 4/7 * ( 117 + x) = 33 * 8 * 3/7* 117
⇒ ( 117 + x ) = 33 * 8 * 3 * 117/13 * 9 * 4 = 198 ⇒ x = ( 198 ? 117) = 81.

Q 7 - If 5 spiders can catch 5 flies in 5 minutes, how many flies can 100 spiders catch in 100 minutes?

A - 100

B - 500

C - 1000

D - 2000

Answer : D

Explanation

Let the required number of flies be x.
More spiders , more flies      ( Direct)
More time, more flies             ( Direct)
Spiders    5 : 100
:: 5 : x
Times   5 : 100
( 5* 5 * x ) = ( 10 0* 100* 5 ) ⇒ x= 100 * 100* 5  / 5 * 5 = 2000 flies.

Q 8 - If the rent for grazing 40 cows for 20 days in Rs 740, how many cows can graze for 30 days on Rs 222?

A - 6

B - 8

C - 5

D - 12

Answer : B

Explanation

Let the required  number of   cows be x.
Less rent, less cows     (Direct)
More days, less cows    (Indirect)
Rent  740 : 222
:: 40 : x
Days  30: 20 
∴ ( 740 * 30 * x) = ( 222 * 20 * 40 ) ⇒ x = 222* 20 * 40 / 740 * 30 = 8 cows.

Q 9 - If 5 engines consume 6 metric tonnes of coal when each is running 9 hour per day, how much coal will be needed for 8 engines , each running 10 hours a days , it being give that 3 engines of former type consume as much as 4 engines of latter type?

A - 8 metric tonnes

B - 80/3 metric tonnes

C - 25/8 metric tonnes

D - 150/25 metric tones

Answer : A

Explanation

Let the quantity of coal required be x metric tonnes.
More engine, more coal     (Direct)
More hrs/days, more coal       (Direct)
More rate of consumption, more coal     (Direct)
Engine           5:8
Hrs/days        9:10                                      :: 6 : x
Rate of consumption      1/3 : 1/4
∴ (5*9*1/3*x) = (8*10 *1/4 *6)⇒ x= 120/15 = 8 metric tonnes.

Q 10 - A garrison had provision for a certain number of days . After 10 days , 1/5 th of the men desert and it is found that the provision will now last just as long as before. How long was that?

A - 35 days

B - 15 days

C - 25 days

D - 50 days

Answer : D

Explanation

Initially, let x men had provisions for y days. Then, x men had provisions for (y-10)  days.
(x- x/5) men had provisions for y days.
∴ x ( y-10) = 4x /5 *y ⇒5xy - 50 x = 4xy
⇒ xy - 50x = 0 ⇒ x (y-50) = 0 ⇒ y = 50.


aptitude_chain_rules.htm

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