Q1 . A and B can construct a building in 25 and 30 days respectively.If they work together.How long will it take for both of them working together to complete the work?
1. 15 days
2. 15/11 days
3. 150/11 day
4. 120/11 day
Correct Answer is
150/11 day
SOLUTION
As work for one day =1/25
Bs work for one day =1/30
.One day of work together is =1/25+1/30=11/150
so time taken=150/11 days
Q2 . If A,B,C can complete a piece of work in 50 days .A and B can complete the work in 60 days.In how many days can the work be completed If C is working alone to complete the entire work?
1. 300 days
2. 200 days
3. 320 days
4. 240 days
Correct Answer is
300 days
SOLUTION
Work of A+B+C=1/50
work of A +B=1/60
so the work done by C=work of A+B+C - work of A+B=1/50-1/60=1/300
so time taken to complete work by C is 300 days
Q3 . It takes 20 men working for 5 days and 9 hours a day to complete a piece of work.In how many days can the work be completed if 10 men are working 6 hours a day to complete the work?
1. 12 days
2. 10 days
3. 15 days
4. 18 days
Correct Answer is
15 days
SOLUTION
Men1 x days1 x hours1=Men2xdays2xhours2 for the same work
20 x 5 x 9=daysx10x6
days=900/60
15 days
Q4 . A and B can complete the work in 15 and 30 days respectively.In how many days will the work be completed if A and B are working alternatively .Find out that who was working while the work got completed?
1. 10 days
2. 20 days
3. 12 days
4. 24 days
Correct Answer is
20 days
SOLUTION
the work done by A and B respectively 1/15 and 1/30 in one day
work done in two days 1/15+1/30=3/30
total time would be 30/3 x2 =20 days
we multiply by 2 as we intially calculated the work done for two days
Q5 . If A,B and C can complete the work in 10 ,20 and 30 days respectively.In how many days can the work be completed if the work is continued by two of them A and B after 2 days of all three working together?
1. 32/9 days
2. 35/9 days
3. 37/9 days
4. 38/9 days
Correct Answer is
38/9 days
SOLUTION
work done by A B C in one day is 1/10+1/20+1/30=11/60
Work in 2 days 2x11/60=22/60
Remaining work 1-22/60=38/60
Work done by A and B in one day is =1/10+1/20=3/20