The ratio of the incomes of two employees is 7 : 4, and the ratio of their expenditures is 3 : 1. If each of them manages to save ₹4,800 per month, find the sum of their monthly incomes (in ₹). 

Find the value of given expression.

30 – [40 – {56 – (25 – 13 – 12)}]

What is the volume of the largest sphere that can be carved out of a wooden cube of side 21 cm?$$( π{22\over 7})$$

A circle touches all four sides of a quadrilateral ABCD. If AB = 18 cm, BC = 21 cm and  = 15 cm, then length CD is: 

A basket contains 350 eggs. If 12% of the eggs are rotten, how many eggs are good enough to be sold?

If interest be compounded half-yearly, then find the compound interest on ₹8,000 at the rate of 20% per annum for 1 year. 

A glass jar contains 6 white, 8 black, 4 red and 3 blue marbles. If a single marble is chosen at random from the jar, what is the probability that it is black or blue?

A,B, C are three points such that AB = 9 cm, BC = 11 cm and AC = 20 cm. The number of circles passing through points A,B,C is: