Permutations and Combinations
56 Questions
1982
JEE Advanced
MCQ
IIT-JEE 1982
Ten different letters of an alphabet are given. Words with five letters are formed from these given letters. Then the numbers of words which have at least one letter repeated are
A.
69760
B.
30240
C.
99748
D.
none of these
1982
JEE Advanced
MCQ
IIT-JEE 1982
The value of the expression $\,{}^{47}{C_4} + \sum\limits_{j = 1}^5 {^{52 - j}\,{C_3}} $ is equal to
A.
${}^{47}{C_5}$
B.
${}^{52}{C_5}$
C.
${}^{52}{C_4}$
D.
none of these
1982
JEE Advanced
Numerical
IIT-JEE 1982
In a certain test, ${a_i}$ students gave wrong answers to atleast i questions, where i = 1, 2,..., k. No student gave more than k wrong answers. The total number of wrong answers given is.....................................
Correct Answer: $${a_1} + {a_2} + ...... + {a_k}$$
1981
JEE Advanced
Numerical
IIT-JEE 1981
Five balls of different colours are to be placed in there boxes of different size. Each box can hold all five. In how many different ways can be place the balls so that no box remains emply?
Correct Answer: 300
1979
JEE Advanced
MCQ
IIT-JEE 1979
${}^n{C_{r - 1}} = 36,{}^n{C_r} = 84\,\,and\,\,{}^n{C_{r + 1}} = 126$, then r is :
A.
1
B.
2
C.
3
D.
None of these.
1978
JEE Advanced
Numerical
IIT-JEE 1978
Six X' s have to be placed in the squares of figure below in such a way that each row contains at least one X. In how many different ways can this be done.
Correct Answer: 26