Solve 10x − 8 = 40 − 2x

The spinner below is spun twice:

The probability of getting two greens is 4/25

Work out the angle of the green sector.

The spinner is spun another three times. Work out the probability than in these three times it lands on one green and two blues.

A lock has four rotating wheels, each
with numbers 0, 1, 2, 3, 4, 5, 6, 7, 8
and 9.

How many different combinations can
be set?

Find the equation of the circle below, which has the origin as its centre: