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 4/5th of a cistern is filled in 1 minute, how much more time will be required to fill the rest of it?
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 - A tree 6m tall casts a 4m long shadow. At the same times, a flagpole casts a 50 m long shadow. How long is the flagpole?
Answer : B
Explanation
Let the length of the flagpole be x metres. Longer is the shadow, longer is the object (Direct) 4: 50 :: 6:x ⇒ 4x = (50 * 6 ) ⇒ x= (50*6 )/4 =75m. Length of flagpole = 75m.
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 - A man and a boy working together can complete a work in 24 days . If for the last 6 days man alone the work , then it is completed in 26 days. How long will the boy take to complete the work alone?
Answer : A
Explanation
Let 1 men 1 days work be 1/x and 1 boy 1 days work be 1/y Then, 1/x + 1/y = 1/24 20/x + 20 / y + 6 /x )1 ⇒ 20 (1/x + 1/y) + 6/x = 1 ⇒ (20 * 24) + 6/x = 1 ⇒ 6/x = (1- 20/24) = 4 / 24 = 1/6 ⇒ 1/x = 1/ 36 ⇒ 1/y = ( 1/24 - 1/ 36 ) = 1/72. ∴ The boy along will do it in 72 days.
Q 5 - 40 men take 8 days to ears Rs 2000. How many men will earn Rs 200 in 2 days?
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 - Four examiners can examine a certain number of answer papers in 10 days by working for 5 hours a day. For how many hours in a day would 2 examiners have to work in order to examine twice the number of answer papers in 20 days?
Answer : D
Explanation
Let the number of hours per days be x.
More days, less hours per days ( Indirect)
Less examiners , more hours per days ( Indirect)
More Ans. Books , more hours per days ( direct)
Days 20 : 10
Examiners 2 : 4 :: 5 : x
Ans. Books 1 : 2
∴ (20 * 2 * 1 * x) = ( 10 * 4 * 2* 5 ) ⇒ x = 400 / 40 = 10 hrs per days.
Q 7 - Running at the same constant rate , 6 identical machines can produce 2700 bottle per minute . At this rate , how many bottles could 10 such machines produce in 4 minutes?
Answer : B
Explanation
Let the required number of bottles be x . More machines, more bottles ( Direct) More time, more bottles ( Direct) Machines 6 : 10 :: 2700 : x Time 1:4 (6 * 1 * x) = 10 * 4 * 2700 ) ⇒ 10 * 4 * 2700 / 6 = 1800 bottles.
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 - If a certain number of workmen can be a piece of work in 25 days , in what time will another set of an equal number of men do a piece of work twice as great , supposing that 2 of the first set can do as much work in an hour as 3 of the second set can do in an hour
Answer : B
Explanation
Let the required time be x days . Ratio of their speed = 1/2 : 1/3. More work , more time (Direct) Less speed, more work (Indirect) Work 1:2 :: 25:x Speed 1/3 : 1/2 ∴ (1* 1/3 *x) = 2 *1/2 *25 ⇒ x=75days.
Q 10 - A contractor undertakes to do a piece of work in 40 days . He engages 100 men at the beginning and 100 more after 35 days and complete the work in stipulated time. If he had not engaged the additional men, how many days behind schedule would it be finished?
Answer : A
Explanation
[(100 *35 ) + (200 *5)] men can finish the work in 1 day. 4500 men can finish it in 1 day ∴ men can finish it in 4500/100 days = 45 days. This is 5 days behind schedule.
