Leo has two boxes of sweets.
In the first box there are 2 strawberry sweets and 3 lemon sweets.
In the second box there are 5 strawberry sweets and 7 lemon sweets.
Leo takes at random a sweet from the first box.
He then takes at random a sweet from the second box.
a.[2]
Complete the probability tree diagram.
b.[2]
Work out the probability that Leo takes two strawberry sweets.