If the mean of -1, 0, 9, 3, k, 5 is 2, where k is a constant, find the median of the set of numbers.

Eight football clubs are to play in a league on home and away basis. How many matches are possible?

Two balls are drawn, from a bag containing 3 red, 4 white and 5 black identical balls. Find the probability that they are all of the same colour.

A force F acts on a body of mass 12kg increases its speed from 5 m/s to 35 m/s in 5 seconds. Find the value of F.

Express the force F = (8 N, 150°) in the form (a i + b j) where a and b are constants.