question_answer

A can do a work in 15 days and 6 in 20 days. If they work on it together for 4 days, then what is the fraction of the work that is left?

A)  \[\frac{1}{4}\]

B)  \[\frac{1}{10}\]

C)  \[\frac{7}{15}\]

D)  \[\frac{8}{15}\]