Each day at the gym, Sarah completes three runs. The distances, in metres, that she completes in the three runs have the independent distributions W ~ N(1520, 450), X ~ N(2250, 720) and Y ~ N(3860, 1050). Find the probability that, on a particular day, Y is less than the total of W and X.

The lengths, in centimetres, of middle fingers of women in Raneland have a normal distribution with mean u and standa…

A selection of 3 letters from the 8 letters of the word COLLIDER is made.

Last Saturday, Sarah recorded the colour and type of 160 cars in a car park. All the cars that were not red or silver…

Let f(x) = (5x² + x + 27) / ((2x + 1)(x² + 9)).

The complex number 1 + 2i is denoted by u.

The line l has equation r = 4i + 3j – k + μ(i + 2j – 2k). The plane p has equation 2x – 3y – z = 4.