Working efficiency of A is 20% more than that of B, who can complete a work 'X' in 36 days.
B and C together started to complete the work 'X' and after 10 days they both left the work and then remaining work is done by A alone in 15 days.
A and C together started to complete another work 'Y' and after working for 12 days they both left the work and Remaining work is done by B alone in 16 days. If D first completed work 'X' and then completed work 'Y' in total 38 days.
It is given that efficiency of all, in completing work 'X' and work 'Y' is same.
A, C and D working simultaneously completed work 'X' in 'n' days and after A, B, C and D working simultaneously completed work. 'Y' in 'm' days. Find the value of (m+n)?

Options

A. 15 days
B. 10 days
C. 12 days
D. 17 days