# Quantitative Aptitude: Time and Work Set 25

1. A can do a piece of work in 25 days. If B is 20% more efficient than A, then in how many days three – fifth of the work is completed by A and B working together ?
2 3/4 days
8 1/5 days
4 days
6 9/11 days
6 11/14 days
Option D
Let efficiency A = 5
efficiency of B = 5 *6 /5 = 6
total work = 25 * 5 = 125
3/5 of the work = 3/5*125 = 75
time = 75/5+6 = 6 9/11days

2. A can do 1/5 of the work in 5 days and B can do 1/4 of the work in 6 days. If they earned total rs.4900, then how much money will A get ?
2400
4800
2500
3200
1450
Option A
A can do total work = 5 * 5 = 25 days
B can do total work = 4 * 6 = 24 days
LCM of 25 and 24 = 600
Total work = 600
efficiency of A = 600/25 = 24
efficiency of B = 600/24 = 25
A get = 4900 * 24/49 = 2400

3. P, Q and R can do a piece of work in 20 days, 30 days and 40 days respectively. If they started the work together but after 6 days P left the work and remaining work done by Q and R together, they in how many days total work will be completed ?
14 days
12 days
20 days
16 days
6 days
Option B
LCM of 20, 30 and 40 = 120
total work = 120
efficiency of P = 120/20 = 6
efficiency of Q = 120/30 = 4
efficiency of R = 120/40 = 3
they completed the work together in 6 days = (6 + 4 + 3)6 = 78
remaining work = 120 – 78 = 42
time taken by Q and R together to complete remaining work = 42/4+3 = 6 days
total time = 6 + 6 = 12 days

4. A group of 25 men is supposed to do a work in 30 days. After 15 days 5 more men is employed and the work is employed in 1 day before the scheduled time. If 5 more men were not employed, then in how many days it have been delayed ?
2
3.2
1.9
2.5
1.8
Option E
work completed by 25 men in 15 days = 25 * 15 = 375
now total men = 25 + 5 = 30
work completed before 1 day
total work = 375 + 30 * 14 = 795
If 5 men is not employed,
time taken by 25 men to complete work = 795/25 = 31.8
work will be delayed = 31.8 – 30 = 1.8 day

5. A and B can do a piece of work in 18 days and 24 days respectively. If they work in alternative day starting with A, then in how many days the work is completed ?
22 2/5
20 4/8
20 1/2
3/4
3
Option C
LCM of 18 and 24 = 72
Total work = 72
efficiency of A = 72/18 = 4
efficiency of B = 72/24 = 3
A and B work in alternate day.
A and B completed work in 2 days = 4 + 3 = 7
10(2 day) = 10(7 work)
20 day = 70 work
A completed 4 work in 1 day so, 2 work completed in 1/2 day.
total time = 20 + 1/2 = 20 1/2 day.

6. A and B can do a piece of work in 25 days and 30 days respectively and they start working together for 10 days. After 10 days A left the work and C joins and the remaining work in completed by B and C together in 5 days. Find the days in which C can do the work ?
50 days
40 days
46 days
32 days
58 days
Option A
LCM of 25 and 30 = 150
total work = 150
efficiency A = 150/25 = 6
efficiency of B = 150/30 = 5
A and B completed work in 10 days = (6 + 5) 10 = 110
remaining of work = 150 – 110 = 40
B and C completed in 5 days = 40/5 = 8
efficiency of C = 8 – 5 = 3
C alone completed total work = 150/3 = 50 days.

7. A and B can do a piece of work in 20 days and 30 days respectively. They start working together after some days A left the work and remaining work completed by B in 15 days. Find in how many days A left the work ?
20
6
4
12
8
Option B
LCM of 20 and 30 = 60
efficiency of A = 60/20 = 3
efficiency of B = 60/30 = 2
B alone work for 15 days = 15 * 2 = 30 work
Time taken to do remaining by A and B together = 30/3+2 = 6 days
After 6 days A left the work.

8. A can do 80% of a work in 20 days. A and B together can do the remaining work in 4 days. Then in how many days B alone would take to do the total work ?
120
130
50
40
100
Option E
A work done = 20*5/4 = 25 days
Remaining work = 1/5
time taken by A and B to do total work = 5 * 4 = 20 days
LCM of 25 and 20 = 100
efficiency of A = 100/25 = 4
efficiency of A and B = 100/20 = 5
efficiency of B = 5 – 4 = 1
Time taken by B to do total work = 100/1 = 100 days

9. P and Q can do a piece of work in 20 days and 40 days respectively. They start the work but Q leaves the work 8 days before the completion. Find how many days is required to complete the work ?
4
8
12
14
20
Option B
LCM of 20 days and 40 days = 40
Total work = 40
efficiency of P = 40/20 = 2
efficiency of Q = 40/40 = 1
work done by P in 8 days = 8 * 2 = 16 days
Remaining work = 40 – 16 = 24 work
Time taken by P and Q remaining work = 24/2+1 = 8 days

10. A and B undertake to complete a work for rs.3000. A and B can do a piece of work on 12 days and 15 days respectively and with the help of C they complete the work in 4 days. Then how much money C get ?
1200
1320
1840
1540
1450
Option A
LCM of 12, 15 = 60
Total work = 60
efficiency of A = 60/12 = 5
efficiency of B = 60/15 = 4
total efficiency of A, B and C = 60/4 = 15
efficiency of C = 15 -(5 + 4) = 6
share of C = 3000 * 6/15 = 1200