A can finish a work in 15 days and B can do the same work in twice the time taken by A. Then, working together, what part of the same work they can finish in five days?
- A1/2
- B4/5
- C1/3
- D1/5
Solution & Step-by-step Explanation
Time taken by A to complete the work = 15 days
Time taken by B to complete the work = 2×15=30 days
Work done by A in 1 day =
15
1
Work done by B in 1 day =
30
1
Work done by A and B together in 1 day:
1 day’s work=
15
1
+
30
1
=
30
2+1
=
30
3
=
10
1
Work done by A and B together in 5 days:
5 days’ work=5×
10
1
=
2
1
Time taken by B to complete the work = 2×15=30 days
Work done by A in 1 day =
15
1
Work done by B in 1 day =
30
1
Work done by A and B together in 1 day:
1 day’s work=
15
1
+
30
1
=
30
2+1
=
30
3
=
10
1
Work done by A and B together in 5 days:
5 days’ work=5×
10
1
=
2
1