EASY
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From a group of 7 men, and 6 women, five persons are to be selected to form a committee so that at least 3 men are there in the committee. In how many ways can it be done?

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Important Questions on Permutation and Combination

MEDIUM
Ten points lie in a plane so that no three of them are collinear. The number of lines passing through exactly two of these points and dividing the plane into two regions each containing four of the remaining points is
MEDIUM
n-digit numbers are formed using only three digits 2, 5 and 7. The smallest value of n for which 900 such distinct numbers can be formed is :
MEDIUM
The number of numbers between 2,000 and 5,000 that can be formed with the digits 0, 1, 2, 3, 4 (repetition of digits is not allowed) and are multiple of 3 is
MEDIUM
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MEDIUM
The number of integers n with 100n999 and containing at most two distinct digits is
EASY
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Five points are marked on a circle. The number of distinct polygons of three or more sides can be drawn using some (or all) of the five points as vertices is
MEDIUM
The number of selection of n objects from 2n objects of which n are identical and the rest are different, is
MEDIUM
In order to get through in an examination of nine papers, a candidate has to pass in more papers than the number of papers in which he fails. The number of ways in which he can fail, in this examination is
HARD
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EASY
Total number of 6-digit numbers in which only and all the five digits 1,3,5,7 and 9 appears, is
EASY
A committee of five members is to be formed out of 3 trainees, 4 professors and 6 research associates. In how many different ways can this be done if the committee should have all the 4 professors and 1 research associate or all 3 trainees and 2 professors?
EASY
If S is a set with 10 elements and A=x, y:x, yS, xy , then the number of elements in A is
EASY
If the number of five digit numbers with distinct digits and 2 at the 10th place is 336k , then k is equal to:
MEDIUM
Let m (respectively, n ) be the number of 5 -digit integers obtained by using the digits 1,2,3,4,5 with repetitions (respectively, without repetitions) such that the sum of any two adjacent digits is odd. Then mn is equal to
EASY
Let S={0,1,2,3,,100}. The number of ways of selecting x, yS such that xy and x+y=100 is
MEDIUM
Let (1+x)n=C0+C1x+C2x2++Cnxn, where Cr=Crn and C0+C1C1+C2Cn-1+Cn=AC1C2Cn, then for n=5, A is equal to
EASY

In how many ways a team of 5 members can be chosen from 8 members?

MEDIUM
From 6 different novels and 3 different dictionaries, 4 novels and 1 dictionary are to be selected and arranged in a row on the shelf so that the dictionary is always in the middle. Then the number of such arrangement is