There are 50 students admitted to a nursery class. Some students can speak only English and some can speak only Hindi. 10 students can speak both English and Hindi. If the number of students who can speak English is 21, then how many students can speak Hindi, how many can speak only Hindi, and how many can speak English?
- A.21, 11 and 29 respectively.
- B.28, 18 and 22 respectively.
- C.37, 27 and 13 respectively.
- D.39, 29 and 11 respectively.
▶ Answer & Explanation
Correct answer: A. 21, 11 and 29 respectively.
In this problem, we are given the total number of students and the number of students who can speak both languages. The number of students who can speak English includes those who speak only English and those who speak both. Using the principle of inclusion-exclusion for sets, we can find the number of students who speak Hindi. The total number of students is the sum of those speaking only English, only Hindi, and both languages.
Source: UPSC csat 2014