B1 and B2 can do a piece of work together in 8 days, B2 and B3 can do the same work together in 16 days, while B1 and B3 can do it together in 32 days. What percentage of the total work can all the 3 people, working together, do in 4 days?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 43.75%.
Calculations:
Total work (LCM of 8, 16 and 32) = 32 units
Efficiency of B1 and B2 = 4
Efficiency of B3 and B2 = 2
Efficiency of B1 and B3 = 1
Now, B1 + B2 + B3 + B2 + B1 + B3 = 7
⇒ 2 × ( B1 + B2 + B3) = 7
Thus, B1 + B2 + B3 = 3.5
They together do 3.5 units in a day.
They will do 14 units in 4 days by working together.
Percentage required = (14/32) × 100 = 43.75%