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.
A car travels at a speed of 60 km per hour from Ernakulam to Trivandrum and returns at a speed of 40 km per hour. Find the average speed.
2 × 3 + 5 – 4 ÷ 2 + 6 × 7 + 82 = ...............