A boy goes to the market at a speed of 10 kmh"1 and returns at a speed of 5 kmh1 . If he takes 3 hours in all, what is the distance between his home and the market ?

A man can row 8 kmh"1 in still water. If the river is running at 2 kmh1 , it takes 4 hrs more upstream than to go downstream for the same distance. Then the distance is given by

If A does a wrok in 1 day then B does it in 3 days (three fast), ie if diff is 2 days then A does then work in 1 day and B in 3 days. But the difference is 40 days. So A does the work in 20 days and B in 60 days.