# 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 - A worker makes a toy every 2/3 hour. If he works for 15/2 hours, then how many toys will he makes?

### Answer : A

### Explanation

Let the required number of toys be x. More time , more toys made (Direct) 2/3 : 15/2 :: 1:x ⇒ 2/3 * x = 15/2 *1 ⇒ x= (15/2 *3/2 ) = 45 /4 = 45/4. Required number of toys = 45/4.

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 - 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 - If 9 men working hours 15/2 hours a day can finish a work in 20 days , then how many days will be taken by 12 men , working 6 hours a day to finish the work . It is given that 2 men of latter type work as much as 3 men of former type?

### Answer : C

### Explanation

2 men of latter type = 3 men of former tyes. 12 men of latter type = (3/2 *12) = 18 men of former tyes. Let the required number of days be x. More men , less days (Indirect) Men 18 : 9 :: 20 : x Working hrs 6 : 15 /2 ∴ 18 *6 *x = 9 * 15/2 * 20 ⇒ x= 9 * 150/18 * 6 = 25/2 = 25/2 days.

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 - If 6 persons working 8 hours a day earn Rs 16800 per week , then 9 persons working 6 hours a day will earn per week?

### Answer : B

### Explanation

Let the required earning be Rs x. More persons , more earning ( Direct) Less hrs per day, less earning ( Direct) Persons 6:9 :: 16800 : x Hrs / day 8 : 6 (6 * 8 *x ) = ( 9 * 6 * 16800) = X =9 * 6 * 16800/ 6 *8 = 18900.

Q 8 - If 18 binders bind 9000 books in 10 days , how many binders will be required to bind 6600 books in 12 days?

### Answer : D

### Explanation

Let the required number of binders be x. Less books, less binders (direct) More days, less binders (Indirect) Books 9000:6600 Days 12:10 :: 18 : x ∴ (9000* 12*x) = (6600 * 10 *18)⇒ x= 6600 * 10 *18/9000 *12 = 11

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 - If x men working x hours per day can do x unit of work in x days , then y men working y hours per day would be able to do how much work in y days?

### Answer : D

### Explanation

More men , more work (Direct) More working hrs , more work (Direct) More days , more work (Direct) Let the required work be z units. Then, Men x:y working hrs x:y :: x:z days x:y ∴ x*x*x*z = y * y* y* x ⇒ z= y^{3}/ x^{2}units.