**841. is able to do a piece of work in 15 days and Q can do the same work in 20 days. If they can work together for 4 days, what is the fraction of work left?****A. 8/15**

B. 7/15

C. 11/15

D. 2/11

**Explanation:****Amount of work P can do in 1 day = 1/15****Amount of work Q can do in 1 day = 1/20****Amount of work P and Q can do in 1 day = 1/15 + 1/20 = 7/60****Amount of work P and Q can together do in 4 days = 4 × (7/60) = 7/15****Fraction of work left = 1 – 7/15= 8/15**

**842. Two pipes P and Q can fill a cistern in 12 min. and 15 min. respectively but a third pipe ‘R’ can empty the full tank in 6 min. P and Q are kept open for 5 min. in the beginning and then ‘R’ is also opened. In what time is the cistern emptied ?**

A. 30 min

B. 35 min

C. 40 min**D. 45 min**

**843. A and B can together do a piece of work in 15 days. B alone can do it in 20 days. In how many days can A alone do it ?**

A. 40 days

B. 50 days**C. 60 days**

D. 70 days

**Explanation:****(A+B)’S 1 day’s work = [1/15−1/20]=1/60****A alone can finish it in 60 days**

**844. Farjan and Kashif can complete a task in 30 days. Farjan leaves after 20 days and Kashif alone completes it in another 25 days. How many days does Farjan alone take to complete the entire task?****A. 50**

B. 75

C. 60

D. 45

**Explanation:****Part of work completed by Farjan and Kashif in a day****= 1/30 Part of work completed by them in 20 days****= 20/30 = 2/3 1/3 of the work is remaining. Kashif completes 1/3rd of the work in 25 days. Part of work completed by him in a day****= (1/3)÷25****= 1/75 (1/D)+(1/V) = 1/30 (1/D) = (1/30)-(1/75) = 1/50 Farjan can complete it in 50 days.**

**845. Jameel can complete a task in 15 hours and Nasir can complete the same task in 12 hours. Jameel starts the task at 9:00 am and stops working at 2:00pm. Nasir starts working on the task at 4:00 pm. At what time is the task completed?**

A. 12:00 pm

B. 2:00 am**C. 12:00 am**

D. 10:00 pm

**Explanation:****Jameel works for 5 hours. So he completes 5/15 = 1/3 of the task Nasir has to complete 2/3rd of the task 12*2/3 = 8 hours are needed. He completes the task at 12:00 am.**

**846. P can do a work in 24 days. Q can do the same work in 9 days and R can do the same in 12 days. Q and R start the work and leave after 3 days. P finishes the remaining work in_________days.****A. 10**

B. 9

C. 11

D. 12

**Explanation:****Work done by P in 1 day = 1/24****Work done by Q in 1 day = 1/9****Work done by R in 1 day = 1/12****Work done by Q and R in 1 day = 1/9 + 1/12 = 7/36****Work done by Q and R in 3 days = 3×7/36 = 7/12****Remaining work = 1 – 7/12 = 5/12****Number of days in which P can finish the remaining work = (5/12) / (1/24) = 10**

**847. Kamal will complete work in 20 days. If Suresh is 25% more efficient than Kamal, he can complete the work in________days.**

A. 14**B. 16**

C. 15

D. 11

**Explanation:****Work done by Kamal in 1 day = 1/20****Work done by Suresh in 1 day = (1/20) × (125/100) = 5/80 = 1/16****=> Suresh can complete the work in 16 days**

**848. A completes 80% of a work in 20 days. Then B also joins and A and B together finish the remaining work in 3 days. How long does it need for B if he alone completes the work?****A. 37 ½ days**

B. 22 days

C. 31 days

D. 22 days

**Explanation:****Work done by A in 20 days = 80/100 = 8/10 = 4/5****Work done by A in 1 day = (4/5) / 20 = 4/100 = 1/25 — (1)****Work done by A and B in 3 days = 20/100 = 1/5 (Because remaining 20% is done in 3 days by A and B)****Work done by A and B in 1 day = 1/15 —(2)****Work done by B in 1 day = 1/15 – 1/25 = 2/75****=> B can complete the work in 75/2 days = 37 ½ days**

**849. 12 buckets of water fill a tank when the capacity of each bucket is 13.5 litres. How many buckets will be needed to fill the same tank, if the capacity of each bucket is 9 litres?**

A. 14

B. 15

C. 16**D. 18**

**Explanation:****Capacity of the tank = (12×13.5)=162 litres****Capacity of each bucket = 9 litres.****Number of buckets needed = 162/9=18**

**850. A leak in the lower portion of a tank can empty the full tank in 9 hrs. An inlet pipe fills water at the rtae of 10 lit. a minute. When the tank is full, the inlet is opened and due to leak, the tank is empty in 16 hrs. How many litres does the cistern hold ?****A. 12,342 litres.**

B. 12,444 litres

C. 12,566 litres.

D. None of these