In a class of 55 students, 15 students liked Maths but not English and 18 students liked English but not Maths. If 5 students did not like both, how many students liked both subjects?
The number of students that liked one more than the other or didn't like either is 15 + 18 + 5, which is 38. The rest of the students in the class liked both subjects. 55 - 38 = 17.