Previous Year Paper
CAT-2008-Previous Years Paper
What is the number of distinct terms in the expansion of (a + b + c)20?
(a + b + c) 20 has each term of the form axbycz where x + y + z = 20. This has 20 + 3–1C3–1 = 231 solutions.
(This question is same as distributing 20 apples among three children where any child can get any number of apples. Formula for this is – n +r–1Cr–1).