A team workers was employed by a contractor who undertook to finish 360 pieces of an article in a certain number of days, Making four more pieces per day then was planned, they could complete the job a day ahead of schedule. How many days did they take to complete the job?
Answer: A Let x be the usual rate of work Then, 360/(x+4) - 360/x =1 On solving we get => x=36 and the number of days = 360/36 = 10
Q. No. 20:
The radius of Cylindrical cistern is 10m and its height is 15m. Initially the cistern is empty. We start filling the cistern with water through a pipe whose diameter is 50cm. Water is coming out of the pipe with a velocity of 5m/s. How many minutes will it take in filling the cistern with water?
Answer: D Number of days taken = 1296/(9*12*8)= 1.5 days Required time = (h*102*15)/(h*0.252*5*60) = 80 min
Q. No. 21:
The work done by a man, a woman and a child are in the ratio 3:2:1. If daily wages of 20 men, 30 women and 36 children amount to Rs 78. What will be the wages of 15men, 21 women and 30 children for 18 weeks?
Answer: A 1/3 M = 1/2 W = 1C => 2M = 3W =6C 20M+ 30W+36C = 60C+60C+36C = 156C If 156 children gets Rs 78, 1 child gets Re 78/156. Now, 15M+21W+30C = 45C+42C+30C = 117C 117 children should gets Rs (78/156 * 117) per day For (18 * 7) days, they should get Rs (18 * 7)(78/156 * 117) = Rs 7371
Q. No. 22:
20 women can do a job in 20 days. After each day, a women is replaced by a man and a man is twice as efficient as a women. On which day does the job completed?
Answer: B Let the total work be 20*20 = 400 unit Hence, a women does 1 unit work per day while, a man does 2 units work per day So, work done on first day(20W) = 20 units. work done on second day (19W+M) = 19+2 = 21 units. On third day = 22 units Thus, work done in 10 days = (21+22+23+24.........+30) =245 units work done in next four days = (31+32+33+34) = 135 units So work done in 14 days = 380 units. The work done on 15th day is 35 units. Hence total work 400 units will be completed on 15th day.
Q. No. 23:
A,B and C can do a piece of work in 36,54 and 72 days respectively. They started the work but A left 8 days before the completion of the work, while B left 12 days before the completion. The number of days for which C worked is
Answer: D Let the work lasted for x days. Then A's (x-8) days work + B's (x-12) days work + C's x days work =1 (x-8)/36 + (x-12)/54 + x/72 =1 => 6(x-8) + 4(x-12) + 3x = 216 => x=24.
Q. No. 24:
12 children take 16 days to complete a work which can be completed by 8 adults in 12 days. 16 adults started working and after 3 days 10 adults left and 4 children joined them. How many days will it take them to complete the remaining work?
Answer: A Let, 1 child's 1 day work = x and 1 adult's 1 day's work =y Then, 12x =1/16 or x = 1/192 and 8y = 1/12 or y= 1/96 work done in 3 days = 16 * 1/96 * 3 = 1/2 Remaining work = 1/2 (6 adults + 4 children)'s 1 day's work = 6/96 + 4/192 = 1/12 1/12 work is done by them in 1 day. 1/2 work is done by them in 12*1/2 = 6 days.