Work done by X in 1 day = 1/25
Work done by Y in 1 day = 1/20
Work done by Y in 12 days = 12/20 = 3/5
Remaining work = 1 – 3/5 = 2/5
Number of days in which X can finish the remaining work = (2/5) / (1/20) = 8
X can finish a work in 25 days. Y can finish the same work in 20 days. Y worked for 12 days and left the job. how many days does X alone need to finish the remaining work?

(A) 2
(B) 5
(C) 6
(D) 7
(E) 8