In the question 2 the fractions involved are 7/10 and 1/2

You are correct! My apologies, I used the wrong fraction for the number of pupils who like Mathematics. Let me correct Q2. (b) i).

Q2. (b)

i) How many girls like Mathematics?
Total pupils in the school = 360.
Pupils who like Mathematics = $\frac{7}{10} \times 360$

$$\text{Pupils who like Mathematics} = 7 \times 36 = 252$$

Half of those pupils who like Mathematics are girls.
Girls who like Mathematics = $\frac{1}{2} \times 252$

$$\text{Girls who like Mathematics} = \boxed{126}$$