Correct option is A
Given:
If A can complete a task in 10 days and
B can complete it in 4 days.
Formula Used:
Total work = Efficiency time
Solution:
If A can complete a task = 10 days
B can complete it = 4 days
Total work done by A and B= LCM(10 , 4) = 20
Total Efficiency of A =
Total Efficiency of B =
A and B together complete the task = days
Hence, option (a) is correct.