Water flows into a reservoir which is 200 m long and 150 m wide, through a pipe of cross-section (0.3m X 0.2m) at 20kmph. In what time will the water level be 8?

Answer:D Explanation:Volume of water collected in the tank in 1 hour ⇒ 0.3×0.2×20×1000=1200 m cubic If after t hours, the water is at height of 8m, 1200t=200×150×8 ⇒ t = 200 Hours.

A work is done by three person A,B and C. A alone takes 10 hours to complete a single product but B and C working together takes 4 hours, for the completion of the same product. If all of them worked together and completed 14 products, then how many hours have they worked?

Answer:C Explanation:1 A =10 and 1 B + 1 C = 1 4 (Given) 1 A + 1 B + 1 C = 1 4 + 1 10 = 7 20 In 20 hours, working together they will complete 7 products. Thus in 40 hours they will complete 14 products

Four men and three women can do a job in 6 days. When five men and six women work on the same job, the work gets completed in 4 days. How many days will a woman take to do the job, if she works alone on it.

Answer:C Explanation:Let the amount of work done by a man in a day be ‘m’ and the amount of work done by a woman in a day be ‘w’. Therefore, 4 men and 3 women will do 4m+3w amount of work in a day. If 4 men and 3 women complete the entire work in 6 days, they will complete ( 1 6 )th of the work in a day. Hence, 4m+3w= 1 6 --------------- (1) and from statement (2), 5m+6w= 1 4 ----------------- (2) Solving eqn (1) and eqn (2), we get 3m= 1 12 or m= 1 36 . i.e. a man does ( 1 36 )th of the work in a day. Hence he will take 36 days to do the work. Substituting the value of m in eqn (1), we get 4× 1 36 +3w= 1 6 ⇒ 3w= 1 6 − 1 9 =3− 2 18 = 1 18 or w= 1 54 . i.e. a woman does ( 1 54 )th of the work in a day. Hence she will take 54 days to do the entire work.

A pump can be used either to fill or to empty a tank. The capacity of the tank is 3600m3. The emptying capacity of the pump is 10m3/min higher than its filling capacity. What is the emptying capacity of the pump if the pump needs 12 more minutes to fill the tank than to empty it?

Answer:B Explanation:Let 'f' m3/min be the filling capacity of the pump. Therefore, the emptying capacity of the pump will be =(f+10)m3/min. The time taken to fill the tank will be= 3600 f minutes And the time taken to empty the tank will be = 3600 f+10 . We know that it takes 12 more minutes to fill the tank than to empty it i.e 3600 f – 3600 f+10 =12 ⇒ 3600f+36000−3600f=12(f2+10f) ⇒ 36000=12(f2+10f) ⇒ 3000=f2+10f ⇒ f2+10f−3000=0. Solving for positive value of 'f' we get, f=50. Therefore, the emptying capacity of the pump =50+10= 60 m3/min

Answer:B Explanation:Even before you start working on the problem, check out if you can eliminate some answer choices as impossible. We know that if A and B alone work, they can complete the job in 6 days. Therefore, if all three of them A, B and C work together the number of days it will take to complete the job will surely be less than 6 days. Hence, we can eliminate answer choices (1) and (4) right away. Let A be the number of days that A will take to complete the job alone, B days for B to complete the job alone and C days for C to complete the job alone. A and B can do a job in 6 days. They complete ( 1 6 )th of the job in a day. i.e. 1 A + 1 B = 1 6 ------- -- (1) Similarly, B and C will complete ( 1 10 )th of the job in a day. i.e 1 B + 1 C = 1 10 ---------- (2) And C and A will complete 1 7.5 or ( 2 15 )th of the job in a day i.e 1 C + 1 A = 2 15 ------------ (3). Adding (1), (2) and (3) we get: 1 A + 1 B + 1 B + 1 C + 1 C + 1 A = 1 6 + 1 10 + 2 15 ⇒ 2 A + 2 B + 2 C = 5+3+4 30 ⇒ 1 A + 1 B + 1 C = 6 30 = 1 5 . i.e working together, A, B and C complete ( 1 5 )th of the job in a day. Therefore, they will complete the job in 5 days.