The diameters of two cones are equal. If their slant heights are in the ratio 5: 2, then the ratio of curved surface areas of the cones is _________ .

A is 80% more than B and C is $$48{4\over 7}\%$$ less than the sum of A and B. By what percent is C less than A?

Mahesh invests a sum of money which becomes Rs. 1344 in 3 years and Rs. 1536 in 7 years. How much had he invested?

The price of sugar is increased by 20%. As a result, a family has to decrease its consumption by 20%. The expenditure of the family on sugar is decreased by

What value will come in place of question mark (?) in the following questions?

(?)² + 1 = 212 + 172

The simple interest on a sum for 5 years is one fourth of the sum. The rate of interest per annum is

Directions: Find the wrong number in the following number series:

141, 156, 147, 162, 153, 165, 159

if 120% of a is equal to 80% of b, then $${b+a}\over {b-a}$$ is equal to