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Q:

Two pipes A and B can fill a tank in 24 hours and  hours respectively. Harihar opened the pipes A and B to fill an empty tank and some times later he closed the taps A and B , when the tank was supposed to be full. After that it was found that the tank was emptied in 2.5 hours because an outlet pipe "C" connected to the tank was open from the beginning. If Harihar closed the pipe C instead of closing pipes A and B the remaining tank would have been filled in :

A) 2 hours B) 8 hours
C) 6 hours D) 4 hours

Answer:   B) 8 hours

Explanation:

Efficiency of Inlet pipe A = 4.16%                              

Efficiency of Inlet pipe B = 5.83%                              

 Efficiency of A and B together = 100 %  

Now, if the efficiency of outlet pipe be x% then in 10 hours the capacity of tank which will be filled = 10 *  (10 - x)

Now, since this amount of water is being emptied by C at x% per hour, then            

           x = 8%

Therefore, in 10 hours 20% tank is filled only. Hence, the remaining 80% of the  capacity will be filled by pipes A and B  in 80/10 = 8 hours 

Q:

Adam and Smith are working on a project. Adam takes 6 hrs to type 36 pages on a computer, while Smith takes 5 hrs to type 40 pages. How much time will they take, working together on two different computers to type a project of 120 pages?

A) 8 hrs 45 min B) 8 hrs 42 min
C) 8 hrs D) 8 hrs 34 min
 
Answer & Explanation Answer: D) 8 hrs 34 min

Explanation:

Number of pages typed by Adam in 1 hour =  = 6
Number of pages typed by Smith in 1 hour =  = 8
Number of pages typed by both in 1 hour = (6 + 8) = 14
Time taken by both to type 110 pages = (120 * 1/14) = 8  = 8 hrs 34 min.

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8 56
Q:

After working for 8 days, Arun finds that only  rd of the work has been done. He employs Akhil who is 60% as efficient as Arun. How many days more would Akhil take to complete the work?

A) 24.5 days B) 26.6 days
C) 25 days D) 20 days
 
Answer & Explanation Answer: B) 26.6 days

Explanation:

Arun has completed  rd of the work in 8 days
Then he can complete the total work in
 ---- 8
1 ---- ?
= 24 days
But given Akhil is only 60% as efficient as Arun
Akhil = 
Akhil can complete the total work in 40 days
Now, remaining 2/3rd of work can be completed in
1 ------   40
  ------   ?    26.66 days.

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8 38
Q:

50 men can build a tank in 40days, but though they begin the work together, 5 men quit every ten days. The time needed to build the tank is ?

A) 50 days B) 48 days
C) 47.5 days D) 49 days
 
Answer & Explanation Answer: A) 50 days

Explanation:

50 men can build a tank in 40 days
Assume 1 man does 1 unit of work in 1 day
Then the total work is 50×40 = 2000 units

50 men work in the first 10 days and completes 50×10 = 500 units of work
45 men work in the next 10 days and completes 45×10 = 450 units of work
40 men work in the next 10 days and completes 40×10 = 400 units of work
35 men work in the next 10 days and completes 35×10 = 350 units of work
So far 500 + 450 + 400 + 350 = 1700 units of work is completed and

remaining work is 2000 - 1700 = 300 units

30 men work in the next 10 days. In each day, they does 30 units of work.

Therefore, additional days required = 

Thus, total 10+10+10+10+10 = 50 days required.

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9 29
Q:

 In a hostel, there was food for 1000 students for one month. After 10 days, 1000 more students joined the hostel. How long would the students be able to carry on with the remaining food?

A) 10 days B) 15 days
C) 20 days D) 5 days
 
Answer & Explanation Answer: A) 10 days

Explanation:

After 10 days, the remaining food would be sufficient for the 1000 students for 20 more days
 If 1000 more students are added, it shall be sufficient for only 10 days (as the no. of students is doubled, the days are halved).

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7 103
Q:

Twenty men can do a work in eighteen days. Eighteen women can complete the same work in fifteen days. What is the ratio between the capacity of a woman and a man ?

A) 4:5 B) 3:4
C) 4:3 D) 2:3
 
Answer & Explanation Answer: C) 4:3

Explanation:

(2018) men can complete the work in in one day.
one man's one day work =
(1815) women can complete the work in 1 day
1 woman's one day work = 
So, required ratio =  = 4:3

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