JEE MATHEMATICS MCQ: PERMUTATIONS

1 Medium

1 of 1

Application +4 | -1

Let

\mathrm{A}

be the set of all positive prime integers less than 30 . The number of different rational numbers whose numerator and denominator belongs to

\mathrm{A}

View answer and explanation

Correct option: A

Option A (90) is correct because the number of different rational numbers is the number of permutations of choosing two distinct primes from the set A.

More Questions from PERMUTATIONS

Practice All Chapter MCQs →

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