A and B together can do a work in 5 days. If A alone can do it in 15 days. In how many days can B alone do it?
Choose the correct answer.
A) 10	B) 99	C) 7.5	D) 55	E) 21
1/5 – 1/15 = 2/15   =&gt; 7.5   Answer: 7.5
<result>C</result>
A and B together can do a work in 5 days. If A alone can do it in 15 days. In how many days can B alone do it?