1.  Sunil complete a work in 4 days whereas Dinesh completes the work in 6 days. Ramesh work 1 times as fast as Sunil. How many days it will take for the three together to complete the work ?
A. 7 / 12
B. 15/12
C. 15/7
D. None of these

Answer: Option D

Explanation:

Time taken by Ramesh alone = (2/3) x 4 = 8/3 days

∴ Their 1 day's work = (1/4 + 1/6 + 3/8) = 19/24

So, together they can finish the work in 24 /19 days, i.e., 15/19 days.