Final answer:
The percentage of students who like both Maths and English is 20%. This is found using the principle of inclusion and exclusion, which factors in the students counted twice in the individual subject preferences.
Step-by-step explanation:
The question is asking to find the percentage of students who like both Maths and English. To solve this, we can use the principle of inclusion and exclusion which states that for any two sets, the size of their union is given by the sum of their sizes minus the size of their intersection.
The percentage of students who like Maths is 75%, and the percentage of students who like English is 70%. It's given that 20% like both subjects. According to the principle, we calculate the union of the two sets (i.e., those who like either Maths or English or both) as:
75% (like Maths) + 70% (like English) - 20% (like both) = 125%
However, since it is not possible to have more than 100% of the students liking either subject, this indicates that the 20% who like both are already included in the individual percentages for Maths and English. Therefore, the correct answer is:
c. 20%