JEE MATHEMATICS MCQ: PERMUTATIONS

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If one test (on screening paper basis) was conducted on Batch A, maximum number of marks is

(90 \times 3)=270.4

students get the marks lower than 80 . Coaching institute decide to inform their guardians, that is why their result card were sent to their home. The number of ways, in which all the letters were put in wrong envelopes, is

View answer and explanation

Correct option: A

Option A (9) is correct because the number of ways to put all 4 letters in the wrong envelopes is calculated using the derangement formula, which results in 9.

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How many different nine digit numbers can be formed from the number 223355888 by rearranging its digits so that the odd digits occupy even positions? The number of ways in which

r

letters can be posted in

n

letterboxes in a town is The number of four-digit numbers that can be made with the digits

1,2,3,4

and 5 in which atleast two digits are identical, is The number of ways in which a pack of 52 cards can be divided equally into four groups, is Five digited numbers with distinct digits are formed by using the digits, 5, 4, 3, 2, 1, 0. The number of those numbers which are multiples of 3, is A man invites a party to

\left( {m + n} \right)

friends to dinner and places m at one round table and

n

at another. The number of ways of arranging the guests is