JEE Main & Advanced
JEE Main Paper (Held On 25 April 2013)
question_answer
5-digit numbers are to be formed using 2,3,5,7,9 without repeating the digits. If p be the number of such numbers that exceed 20000 and \[q\] be the number of those that lie between 30000 and 90000 , then p:q is :
JEE Main Online Paper ( Held On 25 April 2013 )
A) 6:5
B) 3:2
C) 4:3
D) 5:3
Correct Answer:
D
Solution :
P:
0
0
0
0
0
Place
5
4
3
2
1
ways
Total no. of ways \[=5!=120\] Since all numbers are > 20,000 \[\therefore \]all numbers 2,3,5, 7,9 can come at first place.
q:
0
0
0
0
0
Place
3
4
3
2
1
ways
Total no. of ways \[=3\times 4!=72\] (\[\because \] 2 and 9 can not be put at first place) So,\[p:q=120:72=5:3\]