• Placement Papers
• /
• Elitmus
• /
• Numerical Ability
• /
• Number System

Elitmus Question Papers:

(#M40033140) ELITMUS Numerical Ability question permutaion and combination Keep an EYE

How many six digits nos. can be formed using digits 1 to 6 such that no. is always divisible by digit at its unit place??

Asked In Elitmus falak khan (10 years ago)

Unsolved Read Solution (3)

Is this Puzzle helpful?   (2)   (1) Submit Your Solution Number System

Read Solution (3) :

RAKESH  (10 years ago)

unit digit=1,no. is always divisible by 1 => 5!

unit digit=2, no. is always divisible by 2 => 5!

unit digit=3, no. is always divisible by 3 => 5! [sum of digits=1+2+3+4+5+6=21,always divisible by 3]

unit digit=4, no. will be divisible by 4 if 10th digit 2 or 6 => 2* 4!

unit digit=5, no. is always divisible by 5 => 5!

unit digit=6, no. is always divisible by 6 => 5! [as, no. ending with 6 is divisible by 2 & sum of digits=21 so divisible by 3 , hence divisible by 6]

total= 5! + 5! + 5! + 2*4! +5! + 5! = 5*5! + 2*4! = 648

Is this solution Helpfull? Yes (22) | No   

Avinash  (10 years ago)

hello manikandan, why are you simply copying above answers... rather post your own better explanation... I saw your answers in other posts also... so telling this

Is this solution Helpfull? Yes (10) | No   

Mani kandan  (10 years ago)

_ _ _ _ _ 1 =>5!=5*4*3*2*1=120
_ _ _ _ _ 2 =>5!=5*4*3*2*1=120
_ _ _ _ _ 3 =>5!=5*4*3*2*1=120
_ _ _ _ _ 4 =>2*4*3*2*1=48 (Tenth digit can have either 2 or 6)
_ _ _ _ _ 5 =>5!=5*4*3*2*1=120
_ _ _ _ _ 6 =>5!=5*4*3*2*1=120
Total: 120*5 + 48 =648 ans

Is this solution Helpfull? Yes (1) | No (2)  

Please Login to Read Solution.