26.  Two workers A and B working together completed a job in 5 days. If A worked twice as efficiently as he actually did and B worked 1/3 as efficiently as he actually did, the work would have been completed in 3 days. A alone could complete the work in?

5 1/4 days
6 1/4 days
7 1/2 days
none of these

```Answer

Answer: Option  B Explanation:Let A's 1 day's work = x and B's 1 day's work = y.
Then, x+ y = 1/5 and  2x + 1/3y = 1/3.
solving, we get : x = 4/25 and y = 1/25.
therefore A's 1 day's work = 4/25.
so, A alone could complete the work in 25/4 = 6 1/4 days. ```

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27.  P can complete a work in 12 days working 8 hours a day. Q can complete the same work in 8 days working 10 hours a day. If both P and Q work together, working 8 hours a day, in how many days can they complete the work?

5 6/11
6 5/11
5 5/11
6 6/11

```Answer

Answer: Option  C Explanation:P can complete the work in (12*8) hrs. = 96 hrs.                                                                                                                                                                     Q can complete the work in (8*10) hrs. = 80 hrs.
therefore P's 1 hour's work = 1/96 and  Q' s 1 hour's work = 1/80.
(P + Q)'s 1 hour' s work = ( 1/96 + 1/80) = 11/480.
so both P and Q will finish the work in (480/ 11) hrs.
therefore number of days of 8 hours each = (480/11*1/8) = 60/11 days = 5 5/11 days.
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28.  A does a work in 10 days and B does the same work in 15 days. In how many days they together will do the same work?

5 days
6 days
8 days
9 days

```Answer

Answer: Option  B Explanation:A's 1 day's work = 1/10 and B's 1 day's work = 1/15.
therefore (A+B)'s 1 day's work =( 1/10+ 1/15)= 1/6.
so, both together will finish the work in 6 days. ```

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29.  45 men can complete a work in 16 days. Six days after they started working 30 more men joined them.How many days will they now take to complete the remaining work?

5 days
7 days
8 days
6 days

```Answer

Answer: Option  D Explanation:(45*16) men can complete a work in 1 day
1 man's 1 day's work = 1/720
45 men's 6 day's work =(1/16*6) = 3/8, Remaining work = ( 1- 3/8) = 5/8
75 men's 1 day's work = 75/720 = 5/48
Now 5/48 work is done by them in 1 day
5/8 work is done by them in(48/5*5/8) = 6 days ```

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30.  A and B can do a work in 12 days, B and C in 15 days, C and A in 20 days. If A, B and C work together, they will complete the work in

5 days
7 5/6 days
10 days
15 2/3 days

```Answer

Answer: Option  C Explanation:(A+B)' s 1 day's work = 1/12; (B+C)'s 1 day's work = 1/ 15; (A+ C)'s 1 day's work = 1/20.
Adding, we get : 2 (A+B+C)'s 1 day's work = (1/12+1/15+1/20) = 12/60 = 1/5.
therefore (A+B+C)'s 1 day's work = 1/10.
so A,B and C together can complete the work in 10 days. ```

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