26. A test is composed of ten questions each of which must be answered “a” or “b”. If you answer
any 5 questions „a” and any 5 questions „b”, the number of correct answers is guaranteed to be
at least 4. How many answer keys are there with this property?
A) 5^5 B) 252 C) 2 D) 10 E) 22
I will answer your question with a question.
Originally Posted by hasanpak123
How many distinguishable permutations are there of
This is the same as asking how many ten letter words can you make with exactly 2 letters.
Thats 252...What about the 4... Is it just to confuse us? By 'answer key', do they mean the number of solutions we can derive answering each answer 'a' or 'b'?