Hello Aspirants. Welcome to Online Maths in AffairsCloud.com. Here we are creating question sample in **Chain Rule**, which are common for competitive exams. We have included Some questions that are repeatedly asked in exams !!

**10 machines can wash 20 cars in 6 hours. In how many hours can 15 machines wash 40 cars?**

A) 8

B) 7

C) 15

D) 12

E) 6**A) 8**

Explanation:

Washing cars is a work, so

M1*H1*W2 = M2*H2*W1

10*6*40 = 15*H2*20

Solve, H2 = 8 hrs**To build a house, 5 men take 60 days working 8 hours each day. In how many days 2 such houses can be built by 8 men working 10 hours each day?**

A) 75

B) 50

C) 20

D) 60

E) None of these**D) 60**

Explanation:

Building 1 house is 1, 2 houses is 2, so

M1*D1*H1*W2 = M2*D2*H2*W1

5*60*8*(2) = 8*D2*10*(1)

Solve, D2 = 60**2 men and 4 women can complete a job in 5 days. Also same job can be completed by 3 men and 8 women in 3 days. In how many days, twice the job can be completed by 3 men and 3 women?**

A) 4

B) 8

C) 10

D) 8.5

E) 13**B) 8**

Explanation:

2m + 4w = 5D, so 10m + 20w = 1D

3m + 8w = 3D, so 9m + 24w = 1D

So, 10m + 20w = 9m + 24w

Solve, 1m = 4w

From 1st equation(2m + 4w = 5D), 2*4w + 4w = 5D, or 12 women can do in 5 days, so 1 women in 12*5 = 60 days.

Now 3m+3w = 3*4w + 3w = 15 w

1 women in 60 days, so 15 women in 60/15 = 4 days

But we are required to find twice work, so 15 women 1 work in 4 days so twice work in 8 days**A job that can be completed by 2 men and 6 women in 10 days will be completed by 5 men and 15 women in how many days?**

A) 2

B) 3

C) 5

D) 4

E) Cannot be determined**D) 4**

Explanation:

2m + 6w = 10 D

Or 2(1m + 3w) = 10D

Or 1m + 3w = 20D

So 5(1m + 3w) = 20/5

Or 5m + 15w = 4D**There is sufficient food for 40 men for a 15 days picnic. If after 6 days 4 men leave, how many more days can the remaining men intake food?**

A) 8

B) 5

C) 10

D) 1

E) 3**D) 1**

Explanation:

After 6 days, now food is left for 40 men for (15-6) = 9 days, now same food is eaten by (40-4) = 36 men, let it last for x days, so

40*9 = 36*x

Solve, x = 10

The food which was to last for 9 days for 40 men, now will last for 10 days for 36 men, so extra 1 day.**A job is completed by 5 men or 7 women in 40 days, then in how many days thrice the job as previous will be completed by 5 men and 3 women?**

A) 27

B) 28

C) 38

D) 84

E) 90**D) 84**

Explanation:

5 m or 7 w

5m + 3w

Cross multiply and put in denominator

Days = 40*5*7/ [5*3 +7*5] = 28

so for thrice work, days = 28*3**10 women completed 2/7th of work in 18 days working 6 hours each day. After this 5 women left and 2 men joined. In how many days working same number of hours, the remaining work will get completed if 1 man is equal to 2 women?**

A) 50

B) 55

C) 70

D) 58

E) 62**A) 50**

Explanation:

Remaining work = 1 – 2/7 = 5/7

After 18 days, 5 women left and 2 men joined so 4 women joined (1m = 2w), now number of women is 5+4 = 9, so

10*18*6*(5/7) = 9*D2*6*(2/7)

Solve, D2 = 50**20 carpets are to weave by 40 women in 50 days working 8 hours per day. After 20 days, order of 6 more carpets came. To complete the total work on time, how many more hours per day they will have to work?**

A) 2

B) 4

C) 5

D) 10

E) 12**B) 4**

Explanation:

First find the number of carpets weave in first 20 days, after which order of more carpets came. So,

In 50 days, 20 carpets, so in 20 days 20*20/50 = 8 carpets

So in remaining 30 days, (20-8) = 12 carpets can be weave working 8 hrs each day

Now number of carpets is (12+6) = 18, let no of hours is x, so

H1*W2 = H2*W1

8*18 = x*12

Solve, x = 12 hrs

So more hrs = 12-8 = 4 hrs**A work is to completed. 10 men started the work and completed 1/6th of the work in 5 days working 3 hrs each day. 2 more men are employed. In how many days will the total number of men complete four times work as before working 5 hours each day?**

A) 12

B) 18

C) 10

D) 20

E) 15**C) 10**

Explanation:

M2 = (10+2) = 12 men, W2 = 4*(1/6) = 4/6

So

10*5*3*(4/6) = 12*D2*5*(1/6)

Solve, D2 = 10**2 men or 4 women or 5 children can complete a piece of work in 38 days. In how many days will 1 man, 1 woman and 1 child complete the same work?**

A) 20

B) 40

C) 36

D) 42

E) None of these**B) 40**

Explanation:

2 men or 4 women or 5 children = 38 D

So 1m + 1w + 1c = 38*2*4*5/(2*4 + 4*5 + 5*2)

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