Elitmus
Exam
Numerical Ability
Permutation and Combination
there are digits from 1 to 6 .from that 5 digit no are to be formed such that they are divisible by 4. find no of possible combinations?
Read Solution (Total 6)
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- of last two digit divisible by 4 then the no will be divisible by 4.
Here it is not mentioned about repetation so we will check both condition one by one.
A) w/o repeatations.
possible last two digits= 12, 16, 24, 32, 36, 52, 56, 64
so total of 8 ways to fill last two digit.
remaining 3 digits can be filled by (6-2)! =4! ways=24 ways
so total no of ways=24*8=192 ways.
B)with repeataions
possible last two digits= 12, 16, 24, 32, 36,44, 52, 56, 64
so total of 9 ways to fill last two digit.
remaining 3 digits can be filled by 6*6*6 ways=216 ways
so total no of ways=216*9=1944 ways.
now check the given option to get suitable ans.
- 9 years agoHelpfull: Yes(55) No(6)
- There will be 8 different ways to fill the last two digits i.e ;- 12,16,24,32,36,52,56 and 64
For the rest 3 digits we have (6-2)! = 24 ways left
so Total no. of ways = 8*24=192 ways.
(As nothing is mentioned about the repetition so we can take it as repetition is allowed.) - 9 years agoHelpfull: Yes(4) No(0)
- what about 372
- 9 years agoHelpfull: Yes(1) No(4)
- ANS=192
FIND NUMBER WHICH IS DIVISIBLE BY 4 OUT OF (1,2,3,4,5,6)
DIVISIBILITY RULE OF 4 IS=LAST 2 DIGIT DIVISIBLE BY 4 THEN WHOLE NUMBER WILL BE DIVIDED BY 4
12----= (12,16,24,36,52,56,64)-->THIS IS NUMBER WHICH FORM USING 1 TO 6 WHICH IS DIVISIBLE BY 4
16----=
20
24----=
28
32---=-
36----=
40
44
48
52-----=
56-----=
60
64-----=
68
72
4 * 3 * 2 * (TOTAL 8 NUMBER)=24*8=192ANS
---- ------- ------ ---------
- 9 years agoHelpfull: Yes(1) No(0)
- - - - - -(12,16,24,32,36,44,52,56,64)
6*6*6*9=1944 Ans - 9 years agoHelpfull: Yes(0) No(1)
- as it is not mentioned, dat repeation is not allowed...wid reptns........
a/c 2 dat
last 2 digits no i.e., divisible by 4... are 12,16,24,28,32,36,52,56
so der is 8 ways to fill last two digit
remaining 3 places can be filled y 6*6*6 =216
216*8= 1628 - 9 years agoHelpfull: Yes(0) No(1)
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