Question
Five squares of a chessboard are chosen at random, the
probability that three are of one colour and two of another isSolution
5 squares on a chessboard can be chosen in 64C5 ways Three squares of one colour and two squares of different colour can be chosen in two mutually exclusive ways (i) 3 white and 2 black (ii) 3 black and 2 white Thus, the favourable number of cases = 32C3 × 32C2 + 32C2 × 32C3 = 2 × 32C2 × 32C3 Required Probability = 2 × 32C2 × 32C3 / 64C5
If (a2 + 1/a2) = 11, then find the value of (a3 - 1/a3).

If 0.125x3 +0.216y3 = 210 and 0.25x2 + 0.36y2 = 10.30 then find the value of 0.5x + 0.6y.
- If, a 3 Â + b 3 Â = 485 and a + b = 5, then find the value of (1/a) + (1/b) .
If the sum of three numbers is zero, then which of the options below will always be equal to the value of the sum of the cubes of those numbers?
If (a2 + 1/a2) = 18, then find the value of (a3 - 1/a3).
If, 4x + y = 10, and 2xy = 8, and 4x > y, then find the value of 64x³ – y³.
Solve the following system of equations and find (x + y):
2x + 3y = 17
4x − 5y = 1
Find the number of zeroes in 24 × 50 × 64 × 15.