A and B together can do a work in 4 days. If A alone can do it in 20 days. In how many days can B alone do it?  Choose the correct option
A) 11 B) 5 C) 6 D) 8 E) 25
5   5   1/4 â€“ 1/20 = 1/5 =&gt; 5
<result>B</result>
A and B together can do a work in 4 days. If A alone can do it in 20 days. In how many days can B alone do it?