Question

In a class of 30 students, 70% of the students learn English, 40% of the students learn
German and 10% of the students learn both the languages. If all the students learn
either English or German or both the languages, how many more students learn only
English than only German?​

Answer 1

Given info : In a class of 30 students, 70% of the students learn English, 40% of the students learn

German and 10% of the students learn both the languages.

To find : How many more students learn only English than only German ?

solution : total students, n(U) = 30

no of students learn English, n(E) = 70% of n(U) = 70 × 30/100 = 21

no of students learn German, n(G) = 40% of n(U) = 40 × 30/100 = 12

no of students learn both Lang. , n(E n G) = 10% of n(U) = 10 × 30/100 = 3

so no of students learn only English = n(E) - n(E n G) = 21 - 3 = 18

no of students learn only German = n(G) - n(E n G) = 12 - 3 = 9

therefore there (18 - 9) = 9 more students learn only English than only German.

Answer 2

$\huge \tt9$