A soft drinks manufacturer sells bottles of drinks in two sizes. The amount in each bottle, in Mean (ml) Small 252 Large 1012 Variance (m) 4 25 millilitres, is normally distributed as shown in the table:

(a) A bottle of each size is selected at random. Find the probability that the large bottle contains less than four times the amount in the small bottle.

(b) One large and four small bottles are selected at random. Find the probability that the amount in the large bottle is less than the total amount in the four small bottles.