HARD
JEE Main/Advance
IMPORTANT
Earn 100
Ritu has to answer out of questions in an examination. The of ways in which she can answer if she must answer at least of the first five questions is
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Important Questions on Permutations and Combinations
HARD
JEE Main/Advance
IMPORTANT
Let denote the number of ways in which boys can be arranged in a line so that particular boys are separated then, then is equal to
MEDIUM
JEE Main/Advance
IMPORTANT
There are students in a class. The teacher takes of them at a time, to zoological garden as often as he can, without taking the same students more than once. Then the number of visits, the teacher makes to the garden exceeds that of a student by
EASY
JEE Main/Advance
IMPORTANT
The number of non-negative integral solutions of (where is a positive integer) is
MEDIUM
JEE Main/Advance
IMPORTANT
If is the number of positive integral solution of , then
HARD
JEE Main/Advance
IMPORTANT
There are white and red balls marked . The number of ways we can arrange these balls in a row so that neighbouring balls are of different colours is
MEDIUM
JEE Main/Advance
IMPORTANT
There are bulbs in a room. Each one of them can be operated independently. The number of ways in which the room can be lighted is
HARD
JEE Main/Advance
IMPORTANT
The number of six digit numbers that can be form from the digits and . So that the digits do not repeat and the terminal digits are even is
HARD
JEE Main/Advance
IMPORTANT
The number of integers which lie between and and which have sum of the digits equal to is
