A works 3.5 times as fast as B, and A takes 45 days less than B to complete a job when each works alone. Calculate the number of days taken to complete the same job if A and B work together.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 14.
Given that
Time ratio of A and B = 7 : 2
As we know that
The work is inversely proportional to the time
According to the question
The work ratio of A and B = 2 : 7
So, (7 - 2) units = 45 days
5 units = 45 days
1 unit = 9 days
A completes the work in = 2 units = 2 × 9 = 18 days
B completes the work in = 7 units = 7 × 9 = 63 days
Total work = LCM (18, 63) = 126
Hence, work is completed by A and B together in = 126/(2 + 7) = 126/9 = 14 days