Q.1 A can complete a work in 10 days and B in 15 days. How long will they take to complete the work together?
6 days
8 days
9 days
12 days
Explanation - A’s 1 day work = 1/10, B’s 1 day work = 1/15. Together = 1/10 + 1/15 = 1/6. So, they will finish in 6 days.
Correct answer is: 6 days
Q.2 A and B can do a job in 12 days and 15 days respectively. They work together for 5 days. How much of the work is left?
1/4
1/3
7/12
1/5
Explanation - A’s 1 day work = 1/12, B’s = 1/15. Together = 3/20. In 5 days they do 5×(3/20)=3/4, so 1−3/4=1/4 remains.
Correct answer is: 1/3
Q.3 A alone can finish a piece of work in 20 days, while B alone can do it in 30 days. A and B work together for 6 days, then A leaves. How many days will B take to finish the remaining work?
8 days
10 days
12 days
15 days
Explanation - A+B 1 day work = 1/20+1/30=1/12. In 6 days they finish 6/12=1/2. Remaining 1/2 done by B, so 1/2 ÷ (1/30)=15 days.
Correct answer is: 10 days
Q.4 If 10 men can finish a work in 15 days, how many men are needed to finish it in 5 days?
20
25
30
35
Explanation - Work ∝ Men × Days → 10×15= M×5 → M=30.
Correct answer is: 30
Q.5 A can do a work in 8 days, B can do it in 12 days. If they work together and earn Rs. 1000, what is A’s share?
Rs. 400
Rs. 600
Rs. 700
Rs. 800
Explanation - A:B work ratio = 1/8 : 1/12 = 3:2, so A gets 3/5 of 1000 = 600.
Correct answer is: Rs. 600
Q.6 A can do a piece of work in 16 days. B is twice as efficient as A. How long will they take together?
5 days
6 days
8 days
10 days
Explanation - B’s time = 16/2=8 days. Together 1 day work = 1/16+1/8=3/16, total = 16/3 = 5⅓ days.
Correct answer is: 5 days
Q.7 A can finish a job in 5 days and B in 10 days. They work on alternate days starting with A. In how many days will the work be completed?
8 days
9 days
10 days
11 days
Explanation - A+B in 2 days complete 1/5+1/10=3/10. After 6 days 9/10 done. Remaining 1/10 done by A in 0.5 day. Total ≈ 6.5 days.
Correct answer is: 9 days
Q.8 A can do a piece of work in 9 days, B in 12 days. They work together for 3 days, then A leaves. B finishes the rest. Total days?
7 days
8 days
9 days
10 days
Explanation - A+B per day = 1/9+1/12=7/36. In 3 days → 7/12 done. Remaining 5/12 by B alone → 5/12 ÷ 1/12=5 days. Total=8 days.
Correct answer is: 7 days
Q.9 A can do a work in 6 days, B can do it in 8 days, and C can do it in 12 days. Working together, how long will it take?
2 days
3 days
4 days
5 days
Explanation - 1/6+1/8+1/12=3/8. Total=8/3=2.67≈3 days.
Correct answer is: 3 days
Q.10 If A and B together can finish a work in 10 days and A alone can do it in 15 days, how long will B alone take?
20 days
25 days
30 days
40 days
Explanation - A+B =1/10, A=1/15 → B=1/30 → 30 days.
Correct answer is: 30 days
Q.11 A is twice as good a worker as B and together they finish a job in 18 days. How long will B alone take?
36 days
45 days
54 days
60 days
Explanation - If A:B efficiency = 2:1, total work = 3 units/day. A+B 18 days → 54 units → B alone → 54/1=54 days.
Correct answer is: 54 days
Q.12 A can do a job in 40 days. He works alone for 8 days, then B joins and they finish together in 12 more days. How long will B alone take?
20 days
24 days
30 days
40 days
Explanation - A 8 days → 8/40=1/5 done. Remaining 4/5 in 12 days by A+B → (A+B)=1/15, so B=1/15−1/40=1/24.
Correct answer is: 24 days
Q.13 A and B can do a job in 6 days and 8 days respectively. How long will they take if A works for 2 days and B for 3 days alternately until completion?
4 days
5 days
6 days
7 days
Explanation - 2-day A work=2/6=1/3, 3-day B work=3/8=3/8. Total 1/3+3/8=17/24≈0.7. Repetition leads to completion in ~5 days.
Correct answer is: 5 days
Q.14 If 12 men can finish a job in 18 days, how many days will 9 men take for the same work?
20 days
22 days
24 days
27 days
Explanation - Men × Days constant → 12×18=9×D → D=24.
Correct answer is: 24 days
Q.15 A and B can do a piece of work in 10 days, B and C in 15 days, and A and C in 20 days. How long will all three take together?
8 days
9 days
10 days
12 days
Explanation - A+B=1/10, B+C=1/15, A+C=1/20. Add → 2(A+B+C)=1/10+1/15+1/20=13/60 → A+B+C=13/120→time=120/13≈9.2 days.
Correct answer is: 8 days
Q.16 A can finish a job in 25 days and B in 50 days. They work together for 10 days, then B leaves. Remaining work done by A. How many total days?
20 days
25 days
30 days
35 days
Explanation - A+B=1/25+1/50=3/50. 10 days → 3/5 done. Remaining 2/5 by A → 2/5 ÷ 1/25=10 days. Total=20 days.
Correct answer is: 25 days
Q.17 A, B, and C can do a work in 10, 15, and 30 days respectively. How long will A and B take if C leaves after 2 days?
5 days
6 days
7 days
8 days
Explanation - A+B+C=1/10+1/15+1/30=1/5. In 2 days → 2/5. Remaining 3/5 by A+B=1/6 per day → time= (3/5)/(1/6)=3.6 days → total~6 days.
Correct answer is: 6 days
Q.18 If 6 men or 9 women can do a piece of work in 20 days, how many days will 3 men and 6 women take?
15 days
18 days
20 days
25 days
Explanation - 6M=9W → 1M=1.5W. So 3M+6W=4.5+6=10.5W. 9W in 20d → total work=180W-days. Time=180/10.5=17.1≈18 days.
Correct answer is: 20 days
Q.19 A tank can be filled by one tap in 10 hours and emptied by another in 15 hours. If both are opened together, when will it be full?
20 hours
25 hours
30 hours
35 hours
Explanation - In 1 hr: +1/10−1/15=1/30 filled. So full in 30 hrs.
Correct answer is: 30 hours
Q.20 A tap can fill a tank in 8 hours. Another can empty it in 12 hours. If both are opened together, how long to fill?
20 hours
24 hours
30 hours
48 hours
Explanation - Net per hr = 1/8−1/12=1/24 → full in 24 hours.
Correct answer is: 24 hours
Q.21 If A can do a work in 12 days and B in 16 days, they start together but A leaves after 3 days. In how many more days will B finish?
8 days
9 days
10 days
11 days
Explanation - A+B per day=1/12+1/16=7/48. 3 days → 7/16. Remaining 9/16 by B → 9/16 ÷ 1/16=9 days.
Correct answer is: 9 days
Q.22 A and B can do a job in 10 and 20 days respectively. If B works alone for 5 days and A completes the rest, how long total?
6 days
7 days
8 days
9 days
Explanation - B 5 days → 5×1/20=1/4. Remaining 3/4 by A in 3/4 ÷ 1/10=7.5 days total ≈ 8 days.
Correct answer is: 7 days
Q.23 A can finish a work in 18 days and B can do it in 27 days. They start together but B leaves after 6 days. Find total days.
10 days
12 days
14 days
15 days
Explanation - A+B=1/18+1/27=1/10.8. 6 days → 5/9 done. Remaining 4/9 by A → 4/9 ÷ 1/18=8 days. Total=14 days.
Correct answer is: 12 days
Q.24 A and B together can finish a work in 5 days. B alone can do it in 15 days. After how many days should B leave so A alone finishes the rest in 2 more days?
1 day
2 days
3 days
4 days
Explanation - A+B=1/5, B=1/15 → A=1/5−1/15=2/15. Let B worked x days → x/5 work done. Remaining by A in 2 days → 2×2/15=4/15. So x/5+4/15=1 → x=2 days.
Correct answer is: 2 days
Q.25 A and B can do a work in 30 days and 40 days respectively. They work together for 10 days, then A leaves. Find total time.
25 days
30 days
35 days
40 days
Explanation - A+B=1/30+1/40=7/120. 10 days → 7/12. Remaining 5/12 by B → 5/12 ÷ 1/40=16⅔ days. Total ≈ 27 days.
Correct answer is: 30 days