A notebook of length 15 cm was measured to be 16.8 cm, calculate, correct to two d.p, the percentage error in the measurement.

If 2x - 3y = -11 and 3x + 2y = 3, evaluate \( (y - x)^2\)

The diagonals of a rhombus are 16 cm and 12 cm find the length of the side.

M varies jointly as the square of n and square root of q. If M = 24 when n = 2 and q = 4, find M when n = 5, q = 9.

Find the mean deviation of assets of numbers: 14, 15, 16, 17, 18, and 19.