apitude

Question

How many 4 digit no. can b formed wit digits 1, 2, 3,4,5 which r divisible by 4 and digits not repeated?

144 / 168 / 182 / none

Answer 1

Answer is 24.

Last 2 digits should be divisible by 4 for the number to be divisible by 4.Last two digits should be 12 or 32 or 52 or 24 and corresponding to these 4 possibilities we can have 3*2=6 numbers in the starting two digits.

So total 4 digit numbers will be 6*4=24.

Comments

wow :) thanks bhai :)

Answer 2

The answer is clearly none.

The last digit is clearly 4 or 2 for numbers divisible by 4 using the given digits.Lets count total such numbers.

Total numbers ending with 4 = 4c_3*3!(Fix 4 in last position, pick any 3 digits from available 3 digits and 3! is there total permutations)

Total numbers ending with 2= 4c_3*3!(Fix 2 in last position, pick any 3 digits from available 3 digits and 3! is there total permutations) 

Sum = 24+24=48.

The answer is actually less than 48, because not all such numbers will be divisible by 4 Example is 1234.Therefore answer is none.

Answer 3

clearly answer is None (24) because for the any number to be divisible of 4 its last 2 digits should be divisible by 4 here 12,24.32,52 should be last digits now with 12 there will be 6 digits similarly for 24,32,52 18 other numbers also be there so clearly 6*4=24