Two similar solids A and B are shown. B
3 cm
6 cm
Solid A has a volume of 60 cm'.
a) Work out the volume of solid B.
Solid B has a total surface area of 140 cm.
b) Work out the total surface area of solid A.

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?