Class 11

Math

JEE Main Questions

Permutations and Combinations

The value of $r=0∑n−1 _{n}C_{r}/(_{n}C_{r}+_{n}C_{r+1})$ equals a. $n+1$ b. $n/2$ c. $n+2$ d. none of these

Connecting you to a tutor in 60 seconds.

Get answers to your doubts.

The number of possible outcomes in a throw of $n$ ordinary dice in which at least one of the die shows and odd number is a. $6_{n}−1$ b. $3_{n}−1$ c. $6_{n}−3_{n}$ d. none of these

Find the number of ways in which $5A_{prime}sand6B_{′}s$ can be arranged in a row which reads the same backwards and forwards.

The English alphabet has 5 vowels and 21 consonants. How many words with two different vowels and 2 different consonants can be formed from the alphabet?

How many 4-digit numbers are there with no digit repeated?

A number of 18 guests have to be seated, half on each side of a long table. Four particular guests desire to sit on one particular side and three others on the other side. Determine the number of ways in which the sitting arrangements can be made.

How many 5-digit telephone numbers can be constructed using the digits 0 to 9 if each number starts with 67 and no digit appears more than once?

Number of ways in which 30 identical things are distributed among six persons is a.C(17,5) if each gets odd number of things b.C(16,11) if each gets odd number of things c) C(14,5) if each gets even number of things (excluding 0) d. C(15,10)if each gets even number of things (excluding 0)

There are four letters and four directed envelopes. The number of ways in which all the letters can be put in the wrong envelope is a. $8$ b. $9$ c. $16$ d. none of these