The average of 30 numbers is 40 and that of the other 40 numbers is 30. The average of all the numbers is-

Wheat costing Rs. 30/kg, Rs. 35/kg and a third variety of wheat are mixed in the ratio of 3 ∶ 4 ∶ 2. If the mixture costs Rs. 34/kg, then what will be the cost (in Rs./kg) of the third variety of wheat?

If the average weight of 6 students is 50 kg; that of 2 students is 51 kg; and that of other 2 students is 55 kg; then the average weight of all students is

Length of rectangle is 80% of diagonal of square of area 1225, then find area of rectangle if it's perimeter is 94√2.

A sum of money doubles itself in 7 years at simple interest. In how much time will it become 5 times of itself?

The sum of the two - digit number is 6 and the number and its flip (digits written in reverse order) both are multiples of 3. If the difference between them is 36, then which of the following is the required number and its flip? 

A prism and a pyramid have the same base and the same height. Find the ratio of the volumes of the prism and the pyramid.

Directions : The Bar Graph given here shows the population (in crores) of India in various census years. Observe the graph and answer the question based on it.

Peryear increase in population from the year 1931 to 1981 is