A can do a certain work in 15 days, while Working together, A and
| A can do a certain work in 15 days, while Working together, A and B can do the same work in 7.5 days. How many days will B alone take to do the same work?
A. 15 days
B. 12.5 days
C. 17.5 days
D. 20 days
Please scroll down to see the correct answer and solution guide.
Right Answer is: A
SOLUTION
Given,
A can do a certain work in = 15 days
A and B can do the same work in = 7.5 days
Concept:/Formula:
Total work = Efficiency × Time Taken
Calculation:
Total work = 15
Efficiency of A and B = 2
Efficiency of A = 1
Let efficiency of B be x, then
⇒ x + 1 = 2
⇒ x = 2 – 1
⇒ x = 1
B alone can complete the whole work in = 15/1 = 15 days
