Elitmus
Exam
Numerical Ability
Permutation and Combination
how may number are there greater than 6*10^6 by using digits 5,6,9,0 . repetition is not allowed?
a-180
b-520
c- not remember
Read Solution (Total 14)
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- question is wrong ,
Correct question is that asked in elitmus ..
how may number are there greater than 6*10^6 by using digits 5,5,6,6,9,9,0 when repetition is not allowed? - 8 years agoHelpfull: Yes(34) No(5)
- 7 places - _ _ _ _ _ _ _
using permutations rule
1st place - (6,6,9,9) - 4!
similarly,
in order of places- 4 6 5 4 3 2 1
now, since (2,6,9) have commons -
(4*6*5*4*3*2*1)/(2!*2!*2!) = 360 - 8 years agoHelpfull: Yes(33) No(7)
- Numbers should be greater than 6*10^6
It means numbers should start with 6 and 9(from the given digits only this two)
Starting with 6
6 _ _ _ _ _ _
above 5 places can be filled with remaining 6 digits in 6!/(2!*2!) =>180
Starting with 9
9 _ _ _ _ _ _
above 5 places can be filled with remaining 6 digits in 6!/(2!*2!) =>180
Total =180+180 =360 - 8 years agoHelpfull: Yes(30) No(4)
- and its answer is 360.
(4*6!)+(2!*2!*2!*2!) - 8 years agoHelpfull: Yes(9) No(20)
- 360..iam i right!
- 8 years agoHelpfull: Yes(2) No(7)
- since there are 7 places and the no has to be greater than 6*10^6
and the no are 5,5,6,6,9,9,0
_ _ _ _ _ _ _=2*6*5*4*3*2*1=180 - 8 years agoHelpfull: Yes(2) No(3)
- this is not possible as it has to bea seven digit no and not possible with 4 digits
- 8 years agoHelpfull: Yes(1) No(8)
- 7 places - _ _ _ _ _ _ _
1st place - (6 or 9) = 2
similarly,
second place there is (5,6,9,0) = 4
same as other places
2*4*4*4*4*4*4 = 8192 answer
i think some part of question is missing that is why answer is not in options
- 8 years agoHelpfull: Yes(1) No(6)
- @saurabh rathour can u explain the approach plz ?
- 7 years agoHelpfull: Yes(1) No(1)
- bakwas site hai , genuine question ko change karke puchha gaya hai, please don.t use this site anymore
- 7 years agoHelpfull: Yes(1) No(3)
- 520 bt how i dnt know
- 8 years agoHelpfull: Yes(0) No(10)
- since 7 digits are given in the question so any seven digit number formed from the combination of these digits (except the ones starting from zero ) would be greater than 6*10^6.
so the correct method is total of seven digits no. + six digits no. (starting from 0) greater than 6*10^6
i.e. (6*6!)/(2!*2!*2!) + (4*5!)/(2!*2!*2!*) - 8 years agoHelpfull: Yes(0) No(0)
- use this formula n!/(n-r)! n:6 r:4 have fun
- 7 years agoHelpfull: Yes(0) No(2)
- In the question it is given that digits should not be repeted. So how can we use Two five's,two nine's.?
- 7 years agoHelpfull: Yes(0) No(0)
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