Correct option is B
Given:
A and B together complete the work in 2 days
A alone completes it in 4 days
We need to find in how many days B alone can do 17 times the same work
Solution:
A's 1-day work =
A + B’s 1-day work =
B's 1-day work =
So, B can do the full work in 4 days
Now, for 17 times the work:
Time = 17 × 4 = 68 days
Alternate Solution:
Let total work = LCM of 2 and 4 = 4 units
A’s 1-day work = = 1 unit/day
A + B’s 1-day work = = 2 units/day
B’s 1-day work = 2 − 1 = 1 unit/day
So B completes 4 units in 4 days
For 17 × 4 = 68 units, time = = 68 days