If a can do a work in 10 days and a and b can do a same piece of job in 5 days. IN how days can do a work b alone?
Choose the correct answer.
A) 10  B) 20  C) 5  D) 15  E) 9
a's one day work=1/10   a+b=1/5(one day work)   b=(1/5)-a=(1/5)-(1/10)   =1/10(one day work)   b can done a work in 10 days.   10nswer option 10
<result>A</result>
If a can do a work in 10 days and a and b can do a same piece of job in 5 days. IN how days can do a work b alone?