MEDIUM
JEE Main
IMPORTANT
Earn 100

Number of ways in which 7 green bottles and 8 blue bottles can be arranged in a row if exactly 1 pair of green bottles is side by side is (assume all bottles to be alike except for the colour)

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Important Questions on Permutation and Combination

HARD
JEE Main
IMPORTANT
Which of the following is not the number of ways of selecting n objects from 2n objects of which n objects are identical?
HARD
JEE Main
IMPORTANT
A seven-digit number is in the form of abcdefg (g, f, e etc.,, are digits at the units, tens, hundred place, and so on), where a<b<c<d>e>f>g and a, b, c, e, f, g are different digits. The number of such numbers is
HARD
JEE Main
IMPORTANT
The number of all six-digit numbers using digits 1, 2, 3, 4, 5, such that any digit that appears in the number appears at least twice is
HARD
JEE Main
IMPORTANT
All the five-digit numbers N=abcde having the property a<b<c<d<e are arranged in the increasing order of their magnitude. The 97th number in the list does not contain the digit
HARD
JEE Main
IMPORTANT
Find the number of n digit numbers formed by using digits 1, 2, 3, such that if 1 appears, it appears even number of times.
HARD
JEE Main
IMPORTANT
A, B, C and D develop 18 items. That is, five items jointly by A and C, four items by A and D, four items by B and C and five items by B and D. The number of ways of selecting eight items out of 18, so that the selected ones belong equally to A, B, C and D, is
HARD
JEE Main
IMPORTANT
The number of pairs of the diagonals of a regular polygon of 10 sides that are parallel is
HARD
JEE Main
IMPORTANT
Four letters, two a and two b are filled into 16 cells of a matrix as shown in the given figure. It is required that each cell contains at most one letter and each row or column cannot contain the same letters. Then the number of ways the matrix can be filled is

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