In a school of 250 pupils, 100 are girls and 200 pupils stay at school for lunch. If 40 girls go home for lunch, find the number of boys who go home for lunch :
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?
