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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.
Q 1 - If 21 cows eat as much as 15 buffaloes, how many cows will eat as much as 35 buffaloes?
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 - 10 men can finish the construction of a wall in 8 days. How many men are added to finish the work in half a day?
Answer : D
Explanation
Let the total number of men be x. Less days , more men required (Indirect) 1/2 : 8 :: 10 : x ⇒ 1/2 x =(8* 10 )⇒ x= (8* 10* 2*) = 160. Number of men to be added = (160- 10 )=150.
Q 3 - 10 women can complete a piece of work in 8 days and 10 children take 12 days to complete it. How many days will 6 women and 3 children together take to complete the work?
Answer : C
Explanation
1 women can complete the work in ( 10 * 8) = 80 days. 1 child can complete the work in ( 10 * 12) = 120 days. 1 women 1 days work = 1/80, 1 child 1 days work = 1/120. ( 6women + 3 children) 1 days work = ( 6 * 1/80 + 3 * 1/120) = ( 3 /40 + 1/40 ) = 4/40=1/10. Required time 10 days.
Q 4 - 8 men and 12 children can do a piece of work in 9 days . A child takes double the time to do a work than the men. In how many days 12 men can complete the work?
Answer : A
Explanation
2 children = 1 men ⇒ (8 men + 12 children ) = 14 men. Let the required number of days be x. Less men , more day (Indirect ) 12 : 14:: 9 : x ⇒ 12x = ( 14 * 90 ⇒ ( 14* 9 ) /12 = 21 /2 = 21/2 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?
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 garrison of 3300 men had provisions for 32 days , when given at the rate of 850 gm per head . At the end of 7 days , a reinforcement arrived and it was found that the provisions would last 17 days more , when given at the rate of 825 gm per head . What was the strength of the reinforcement?
Answer : C
Explanation
Let the required strength of reinforcement be x. 3300 men had provisions for (32-7 ) = 25 days. Less food per head , more persons (Indirect) Less days , more persons (Indirect) Food per days 825 : 850 :: 3300 : (3300 x ) Days 17 : 25 ∴ 825 * 17 * (3300 + x ) = 850 * 25 * 3300 ⇒ ( 3300 + x ) = 850 * 25 * 3300/825 * 17 = 5000 ⇒ x = ( 5000 - 3300) = 1700 men.
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?
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 - If the rent for grazing 40 cows for 20 days in Rs 740, how many cows can graze for 30 days on Rs 222?
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 - 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 . 8 men and 6 boys can do 3 times the amount of this work in
Answer : A
Explanation
Let 1 men 1 days work be 1/x and 1 boy 1 day work be 1/y Then 2/x + 7/y = 1/14 ⇒ 2u + 7v = 1/14 -(i) When u= 1/x, v=1/y. 3/x +8/y =1/11 ⇒ 3u + 8v = 1/11?.(ii) Multiplying (i) by (ii) by 2 and subtracting , we get: 5v = ( 3/14 ? 2/11) = 5/ 154 ⇒ v = 1/154 Putting v = 1/154 in (i) we get : 2u +7* 1/154 = 1/14 ∴ 2u = (1/14- 1/22)= (11-7/54) = 4/154 = 2/77 ⇒ u=1/77. (8 men +6 boys) 1 days work = (8/77 +6/154 ) = 22/154 = 1/7. ∴ 8men and 6 boys can do it in 7 days. They will do thrice of this work in (3*7) days = 21days.
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?
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.