25
Q:

A Contractor employed a certain number of workers  to finish constructing a road in a certain scheduled time. Sometime later, when a part of work had been completed, he realised that the work would get delayed by three-fourth of the  scheduled time, so he at once doubled the no of workers and thus he managed to finish the road on the scheduled time. How much work he had been completed, before increasing the number of workers?

A) 10 % B) 14 2/7 %
C) 20 % D) Can't be determined

Answer:   B) 14 2/7 %



Explanation:

Let he initially employed x workers which works for D days and he estimated 100 days for the whole work and then he doubled the worker for (100-D) days.

      D * x +(100- D) * 2x= 175x

       =>  D= 25 days

Now , the work done in 25 days = 25x

               Total work = 175x

therefore, workdone before increasing the no of workers = \frac{25x}{175x}\times 100=14\frac{2}{7} %

Q:

P is 30% more efficient than Q. How much time will they, working together, take to complete a job which P alone could have done in 23 days?

A) 16 days B) 13 days
C) 15 days D) 12 days
 
Answer & Explanation Answer: B) 13 days

Explanation:

Ratio of times taken by P & Q = 100 : 130 = 10:13

Let Q takes x days to do the work

Then, 10:13 :: 23:x

=> x = 23x13/10

=> x = 299/10

P's 1 day's work = 1/23

Q's 1 day's work = 10/299

(P+Q)'s 1 day's work = (1/23 + 10/299) = 23/299 = 1/13

Hence, P & Q together can complete the work in 13 days.

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10 249
Q:

If 2 men and 3 women can do a piece of work in 8 days and 3 men and 2 women in 7 days. In how many days can the work be done by 5 men and 4 women working together?

A) 3 days B) 6 days
C) 4 days D) 2 days
 
Answer & Explanation Answer: C) 4 days

Explanation:

From the given data,

=> (2 M + 3W) 8 = (3M + 2W)7

=> 16M + 24W = 21M + 14 W

=> 10W = 5M

=> 2W = M

=> 14W × ? = 7W × 8

? = 4 days

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11 316
Q:

28 Men and 52 women working together completes a work in 22.5 days. 35 men and 65 women working together on same work will complete it in how many days?

A) 16 B) 18
C) 19 D) 21
 
Answer & Explanation Answer: B) 18

Explanation:

clearly total persons are increased in => 28/35 :: 52/65 = 4:5

As time is inversely proportional to men, so total time will decrease in the ratio 5:4

Hence, 22.5 x 4/5 = 18 days.

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7 174
Q:

A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left?

A) 8/15 B) 7/9
C) 6/13 D) 4/11
 
Answer & Explanation Answer: A) 8/15

Explanation:
P's 1 day's work = 1  
15
Q's 1 day's work = 1  
20
(P + Q)'s 1 day's work = ( 1 + 1 ) = 7  
15 20 60
(P + Q)'s 4 day's work = ( 7 x 4 ) = 7  
60 15
Therefore, Remaining work = ( 1 - 7 ) = 8 .
15 15
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7 232
Q:

X can complete the work in 10 days, Y can do the same in 15 days. If they are hired for 5 days to do the work together, what is the work that left unfinished?

A) 1/3 B) 2/3
C) 1/6 D) 5/6
 
Answer & Explanation Answer: C) 1/6

Explanation:

Given X can do in 10 days

=> 1 day work of X = 1/10

Y can do in 15 days

=> 1 day work of Y = 1/15

1day work of (X + Y) = 1/10 + 1/15 = 1/6

Given they are hired for 5 days

=> 5 days work of (X + Y) = 5 x 1/6 = 5/6

Therefore, Unfinished work = 1 - 5/6 = 1/6 

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8 373