A class has 50 pupils. 20 like Math only, 15 like English only, and 5 like neither subject. Find the number of pupils who like Math.

The total number of pupils is the sum of pupils in all regions:

$$\text{Total} = (\text{M only}) + (\text{E only}) + (\text{Both}) + (\text{Neither})$$ $$50 = 20 + 15 + K + 5$$ $$50 = 40 + K$$ $$K = 50 - 40$$ $$K = 10$$

Pupils who like Mathematics include those who like Mathematics only and those who like both subjects.

$$\text{Pupils who like Mathematics} = (\text{M only}) + (\text{Both})$$ $$\text{Pupils who like Mathematics} = 20 + 10$$ $$\text{Pupils who like Mathematics} = 30$$

The number of pupils who like Mathematics is $\boxed{\text{30}}$.

Question 22:
The figure shows a triangle KLM with angles:

• $\angle M = (2y + 20)^\circ$
• $\angle K = (3y + 10)^\circ$
• $\angle L = (y + 30)^\circ$

a) Find the value of y.

$$\angle M + \angle K + \angle L = 180^\circ$$ $$(2y + 20) + (3y + 10) + (y + 30) = 180$$

$$(2y + 3y + y) + (20 + 10 + 30) = 180$$ $$6y + 60 = 180$$

$$6y = 180 - 60$$ $$6y = 120$$ $$y = \frac{120}{6}$$ $$y = 20$$

The value of $y$ is $\boxed{20}$.

b) Work out the size of angle KLM.

$$\angle KLM = (y + 30)^\circ$$ $$\angle KLM = (20 + 30)^\circ$$ $$\angle KLM = 50^\circ$$

The size of angle KLM is $\boxed{50^\circ}$.

Question 23:

a) Write the integer represented by the arrow on the number line above.

i) a = $\boxed{4}$

ii) b = $\boxed{-3}$

iii) c = $\boxed{2}$

b) Write down the mathematical statement shown on the number line above.
The number line shows a segment from -3 to 2, inclusive.
The mathematical statement is $\boxed{-3 \le x \le 2}$.

Question 24:
The table shows marks scored by some pupils in a Mathematics test.
Marks: 80, 70, 60, 90
Number of pupils: (empty row)

No questions are provided for this table, and the "Number of pupils" row is empty. Therefore, this question cannot be answered with the given information.