a) 2.75 days
b) 3.75 days
c) 4.75 days
d) 5.75 days
Explanation:
1/6 + 1/10 = 8/30 = 4/15
15/4 = 3.75 days
2. A and B together can do a piece of work in 8 days. If A alone can do the same work in 12 days, then B alone can do the same work in?
a) 24 days
b) 14 days
c) 36 days
d) 30 days
Explanation:
B = 1/8 – 1/2 = 1/24 => 24 days
3. A can do a piece of work in 4 days. B can do it in 5 days. With the assistance of C they completed the work in 2 days. Find in how many days can C alone do it?
Source: safalta.com
a) 15 days
b) 25 days
c) 10 days
d) 20 days
Explanation:
C = 1/2 - 1/4 - 1/5 = 1/20 => 20 days
4. A and B can do a piece of work in 6 2/3 days and 5 days respectively. They work together for 2 days and then A leaves. In how many days after that B will complete the work alone.
a) 4 ½ days
b) 3 ½ days
c) 1 ½ days
d) 2 ½ days
Explanation:
3/20 * 2 + (2 + x)/5 = 1
x = 1 ½ days
5. A can do a piece of work in 30 days. He works at it for 5 days and then B finishes it in 20 days. In what time can A and B together it?
a) 11 (1/3) days
b) 12 (1/3) days
c) 13 (1/3) days
d) 14 (1/3) days
Explanation:
5/30 + 20/x = 1
x = 24
1/30 + 1/24 = 3/40
40/3 = 13 (1/3) days
6. A and B can do a piece of work in 12 days and 16 days respectively. Both work for 3 days and then A goes away. Find how long will B take to complete the remaining work?
a) 6 days
b) 12 days
c) 9 days
d) 8 days
Explanation:
3/12 + (3 + x)/16 = 1
x = 9 days
7. A and B can do a piece of work in 3 days, B and C in 4 days, C and A in 6 days. How long will C take to do it?
a) 24 days
b) 12 days
c) 18 days
d) 30 days
Explanation:
2c = ¼ + 1/6 – 1/3 = 1/12
c = 1/24 => 24 days
8. A can do a piece of work in 10 days. He works at it for 4 days and then B finishes it in 9 days. In how many days can A and B together finish the work?
a) 10 days
b) 18 days
c) 6 days
c) 12 days
Explanation:
4/10 + 9/x = 1 => x = 15
1/10 + 1/15 = 1/6 => 6 days
9. A can do a piece of work in 40 days; B can do the same in 30 days. A started alone but left the work after 10 days, then B worked at it for 10 days. C finished the remaining work in 10 days. C alone can do the whole work in?
a) 36 days
b) 12 days
c) 18 days
d) 24 days
Explanation:
10/40 + 10/30 + 10/x = 1
x = 24 days
10. A work which could be finished in 9 days was finished 3 days earlier after 10 more men joined. The number of men employed was?
a) 20
b) 30
c) 10
d) 40
Explanation:
x ------- 9
(x + 10) ---- 6
x * 9 = (x + 10)6
x = 20