How to speak English like natives (pronunciation tips) #shorts

With reference to the treaties made by the English with native rulers of India in the 18th century, which one of the following pairs is NOT correctly matched ?

There are 50 students admitted to a nursery class. Some students can speak only English and some can speak only Hindi. Ten 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 only English?