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A and B can do a piece of work in 40 days, B and C can do it in 120 days. If B alone can do it in 180 days, in how many days will A and C do it together?

A.

40

B.

45

C.

43

D.

42

Answer with explanation

Answer: Option BExplanation

A + B takes 40 days. B alone takes 180 days.

∴ A will take 1/40 – 1/180 = 7/360 ⇒ 360/7 days.

B + C takes 120 days.

∴ C alone will take 1/120 – 1/180 = 1/360 i.e. 360 days.

∴ A & C together will take 7/360 + 1/360= 8/360

⇒ 360/8 = 45 days to complete the work.

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A, B and C can do a piece of work in 24 days, 30 days and 40 days respectively. They began the work together but C left 4 days before the completion of the work. In how many days was the work completed?

A.

10

B.

11

C.

12

D.

13

Answer with explanation

Answer: Option BExplanation

One day’s work of A, B and C = (1/24 + 1/30 + 1/40) = 1/10.

C leaves 4 days before completion of the work, which means only A and B work during the last 4 days.

Work done by A and B together in the last 4 days = 4 (1/24 + 1/30) = 3/10.

Remaining Work = 7/10, which was done by A,B and C in the initial number of days.

Number of days required for this initial work = 7 days.

Thus, the total numbers of days required = 4 + 7 = 11 days.

Workspace

Vijay can complete a work in 20 days, what percentage of the work would be completed in 6 days?

A.

30%

B.

40%

C.

50%

D.

60%

Answer with explanation

Answer: Option AExplanation

**Given**Vijay can complete a work in 20 days

percentage of work would be completed in 6 days = ( 6 / 20 ) * 100=30%

Workspace

A.

18

B.

15

C.

22

D.

Data inadequate

Answer with explanation

Answer: Option BExplanation

One man’s one day’s work = 1/48

One woman’s one day’s work = 1/60

6 men’s 2 day’s work = ((6/48) x 2) = 1/4

Remaining work = 3/4

Now, 1/60 work s done in 1 day by 1 woman.

Thus, 3/4 work will be done in 3 days by (60 x (3/4) x (1/3)) = 15 women.

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Rajesh alone can do a piece of work in 6 days and Ramesh alone in 8 days. A and B undertook to do it for Rs. 3200. With the help of Suresh, they completed the work in 3 days. How much is to be paid to Suresh?

A.

400

B.

700

C.

500

D.

275

Answer with explanation

Answer: Option AExplanation

Workspace

Mr. A and Mr. B can do a piece of work in 8 and 12 days respectively. If both of them work together, in how many days the work will get completed ?

A.

20 days

B.

4 days

C.

24/5 days

D.

10 days

Answer with explanation

Answer: Option CExplanation

A ‘s 1-day work = 1/8 B’s 1-day work = 1/12

When both work together, 1 day’s work = (1/8) + (1/12) = (3+2)/24 = 5/24

Number of days to complete the work will be 24/5 days

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A alone can do a piece of work in 6 days and B alone in 8 days. A and B undertook to do it for Rs. 3200. With the help of C, they completed the work in 3 days. How much is to be paid to C

A.

Rs. 300

B.

Rs. 400

C.

Rs. 500

D.

Rs. 600

Answer with explanation

Answer: Option BExplanation

Workspace

How many times will minute hand and hour hand opposite in one day?

A.

21

B.

23

C.

22

D.

24

Answer with explanation

Answer: Option CExplanation

Eleven times in 12 hrs. The hands will be directly opposite each other at the following times:

12:32 and 8/11 of a minute

1:38 and 2/11 of a minute

2:43 and 7/11 of a minute

3:49 and 1/11 of a minute

4:54 and 6/11 of a minute

6:00

7:05 and 5/11 of a minute

8:10 and 10/11 of a minute

9:16 and 4/11 of a minute

10:21 and 9/11 of a minute

11:27 and 3/11 of a minute.

**Therefore, the hands of the clock will be opposite to each other 22 times.**

Workspace

A.

50

B.

10

C.

40

D.

20

Answer with explanation

Answer: Option BExplanation

Let the number of workers be x.

Now, Using work equivalence method,

X + (X-1) + (X-2)+ . . . . + 1 = X *55% of X

=> [X * (X+1)] / 2 = X * (55X/100) [because, Series is in AP. Sum of AP = {No. of terms (first term+ last term)/2} ]

Therefore, X = 10

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