Latest self Aptitude Question SOLUTION: How many 9 digit numbers are possible by using the digits 1,2,3,4,5 which are divisible by 4 if therepetition is allowed? a)5^7 b)5^6 c)5^9 d)5^8

• Placement Papers
• /
• self

self Question Papers:

(#M40002574) SELF question Keep an EYE

How many 9 digit numbers are possible by using the digits 1,2,3,4,5 which are divisible by 4 if therepetition is allowed?
a)5^7 b)5^6 c)5^9 d)5^8

Solution

_ _ _ _ _ _ _ _ _ (9 digit number)
Digits that can be used = 1, 2, 3, 4 and 5
For a number to divisible by 4, the last two digits have to be divisible by 4
So, the units digit cannot be 1, 3 or 5
If the units digit is 2, only 12, 32 adn 52 are acceptable as the last two digits
If the units digit is 4, only 24 and 44 are acceptable as the last two digits.
So, total 5 cases 12,24,32,44,52 are possible for the last two digits.
Now, the first 7 digits of the 9 digit number can be filled in 5^7 ways as each place can be filled by 1, 2, 3, 4 or 5.
So, desired answer = 5^7*5 = 5^8
This answer is given by Amitesh kumar and is right

Like manish sir answer on facebook.

aniruddha mandal (12 years ago)

Solved Read Solution (2)

Is this Puzzle helpful?   (3)   (2) Submit Your Solution

Read Solution (2) :

deependra singh chauhan  (12 years ago)

the 9 digit number which is divisible by 4=5^(9-1)=5^8 answer i m correct
given option r not correct

Is this solution Helpfull? Yes (5) | No (2)  

Prasenjit Boral  (12 years ago)

the answer will be 5*5^8=5^9

Is this solution Helpfull? Yes (1) | No (4)  

Please Login to Read Solution.