HARD
JEE Advanced
IMPORTANT
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Let X be a set with exactly 5 elements and Y be a set with exactly 7 elements. If α is the number of one-one functions from XY and β is the number of onto functions from YX, then the value of 15!β-α is _____-.

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Important Questions on Permutation and Combination

HARD
JEE Advanced
IMPORTANT
Let S=1,2,3,.9. For k=1,2,5, let Nk be the number of subsets of S, each containing five elements out of which exactly k are odd. Then N1+N2+N3+N4+N5=
HARD
JEE Advanced
IMPORTANT
Six cards and six envelopes are numbered 1, 2, 3, 4, 5, 6 and cards are to be placed in envelopes so that each envelope contains exactly one card and no card is placed in the envelope bearing the same number and more over the card numbered 1 is always placed in envelope numbered 2. Then the number of ways it can be done is
MEDIUM
JEE Advanced
IMPORTANT
The number of 5 digit numbers which are divisible by 4, with digits from the set {1,2,3,4,5} and the repetition of digits is allowed, is _____.
MEDIUM
JEE Advanced
IMPORTANT
A debate club consists of 6 girls and 4 boys. A team of 4 members is to be selected from this club including the selection of a captain (from among these 4 members) for the team. If the team has to include at most one boy, then the number of ways of selecting the team is