evaluation in language

The story of evolution of modern man is most interesting and appears to ________ of human brain and language. Find the option which fills blank correctly.

In a committee, 40 person can speak Hindi 20 can speak English and 10 can speak both languages. Find how many persons can speak atleast one language ?

In a group of 400 persons 250 can speak Hindi and 200 can speak English. Each person speak atleast one language. Find how many persons can speak both languages ?

In a certain code language, "HELP" is written as "GDKO". How is "FIND" written in that code language?