A and B are in the ratio 5:3; if A=35: B is:
A and B together can do a piece of work in 6 days. A alone can do it in 8 days. In how many days can B alone do it?
(1/4)-2 is :
A father is twice old as his son. Twenty years ago he was 6 times of his son’s age at that time. Find the current age of the father?
If thirty observation have an average of 20 and 20 observations have a mean of 30 then what is the average of all observations?
If the radius of a sphere is 3cm, then its volume is ...................cm3.