**871. P works twice as fast as Q. If Q alone can complete a work in 12 days, P and Q can finish the work in________days**

A. 1

B. 2

C. 3**D. 4**

**Explanation:****Work done by Q in 1 day = 1/12****Work done by P in 1 day = 2 × (1/12) = 1/6****Work done by P and Q in 1 day = 1/12 + 1/6 = ¼****=> P and Q can finish the work in 4 days**

**872. P is 30% more efficient than Q. P can complete a work in 23 days. If P and Q work together, how much time will it take to complete the same work?**

A. 9

B. 11

C. 23**D. 13**

**Explanation:****Work done by P in 1 day = 1/23****Let work done by Q in 1 day = q****q × (130/100) = 1/23****=> q = 100/(23×130) = 10/(23×13)****Work done by P and Q in 1 day = 1/23 + 10/(23×13) = 23/(23×13)= 1/13****=> P and Q together can do the work in 13 days**

**873. 6 men and 8 women can complete a work in 10 days. 26 men and 48 women can finish the same work in 2 days. 15 men and 20 women can do the same work in_______days.****A. 4 days**

B. 6 days

C. 2 days

D. 8 days

**Explanation:****Let work done by 1 man in 1 day = m and work done by 1 woman in 1 day = b****Work done by 6 men and 8 women in 1 day = 1/10****=> 6m + 8b = 1/10****=> 60m + 80b = 1 — (1)****Work done by 26 men and 48 women in 1 day = 1/2****=> 26m + 48b = ½****=> 52m + 96b = 1— (2)****Solving equation 1 and equation 2. We get m = 1/100 and b = 1/200****Work done by 15 men and 20 women in 1 day****= 15/100 + 20/200 =1/4****=> Time taken by 15 men and 20 women in doing the work = 4 days**

**874. A cistern has two taps which fill it in 12 min. and 15 min.respectively There is one outlet pipe in the cistern. When all the taps & pipe are opened, the empty cistern is full in 20 min. How long will the waste pipe (outlet) take to empty the full cistern ?****A. 10 min**

B. 20 min

C. 30 min

D. 40 min

**Explanation:****Work done by waste pipe in 1 minute****=1/20−(1/12+1/15)=−1/10****Waste pipe will empty the full cistern in 10 minutes.**

**875. To fill a cistern, pipes P, Q & R take 20, 15 & 12 minutes respectively. The time in minutes that the three pipes together will take to fill the cistern is:__________?****A. 5 min**

B. 10 min

C. 15 min

D. 20 min

**876. A alone can finish a work in 10 days and B alone can do it in 15 days. If they work together and finish, then out of a total wages of Rs.75. A will get:___________?**

A. 35 Rs.

B. 40 Rs.**C. 45 Rs.**

D. None of these

**Explanation:****Ratio of time taken by A and B= 10 : 15 = 2 : 3****Ratio of work done in the same time = 3:2, So, the money is to be divided among A and B in the ratio 3 : 2****A’s share = Rs. [75×3/5] = Rs.45.**

**877. 2 men and 12 women can finish a job in 4 days. 4 men and 6 women can do the same job in 5 days. Find the time taken by 1 man and 1 woman to complete the job.**

A. 30 days

B. 25 days**C. 24 days**

D. 20 days

**Explanation:****Part of work done by 1 man in a day = 1/m Part of work done by 1 woman in a day****= 1/w (2/m)+(12/w) = (1/4) (4/m)+(6/w) = (1/5) Solving,****1/m = 1/40 ,1/w = 1/60 (1/m)+(1/w) = 5/120 = 1/24**

**878. Bilal can do a work in 15 days and Jalal in 12 days. If they work on it together for 4 days, the fraction of work that is left is________?**

A. 3/5

B. 4/7**C. 2/5**

D. 1/4

**Explanation:****Part of work completed by Bilal in a day = 1/15 Part of work completed by Jalal in a day = 1/12 Part of work completed by them in a day = (1/15)+(1/12) = 3/20 Part of work completed by them in 4 days = (3/20)*4 = 3/5 Fraction of work left****= 1-(3/5)****= 2/5**

**879. A and B can finish a piece of work in 20 days .B and C in 30 days and C and A in 40 days. In how many days will A alone finish the job?****A. 48**

B. 34(2/7)

C. 44

D. 45

**Explanation:****(1/A)+(1/B) = (1/20) (1/B)+(1/C) = (1/30) (1/A)+(1/C) = (1/40) Solving the three equations,****A=48**

**880. If X and Y complete a certain work in 10 days, Y and Z in 16 days and X and Z in 22 days, find the time required for each one to complete the work while working separately.****A. 120, 40, 60 days**

B. 120, 60, 80 days

C. 40, 30, 120 days

D. 30, 40, 60 days

**Explanation:****Let a: be the time in which X & Y completes their work = 30 days****b: time in which Y & Z completes their work = 24 days****c: time in which X & Z completes their work = 40 days****X alone can complete the work in (2 * a * c) / (ab + bc – ac) days****= 2 * 30 * 24 * 40 / ((30 * 24) + (24 * 40) – (30 * 40)) = 120 days****Y alone can complete the work in 2 * a * b * c / (- ab + bc + ac) days****= 2 * 30 * 24 * 40 / (-(30 * 24) + (24 * 40) + (30 * 40)) = 40 days****Z alone can complete the work in 2 * a * b * c / (ab – bc + ac) days****= 2 * 30 * 24 * 40 / ((30 * 24) – (24 * 40) + (30 * 40))****= 60 days**