Permutations And Combinations Question 170

Question: How many numbers can be made with the digits 3, 4, 5, 6, 7, 8 lying between 3000 and 4000, which are divisible by 5 while repetition of any digit not allowed in any number?

Options:

A) 60

B) 12

C) 120

D) 24

Show Answer

Answer:

Correct Answer: B

Solution:

  • [b] 3 must be at thousand’s place and since the number should be divisible by 5, or 5 must be at unit’s place. Now we have to fill two places (tens and hundreds), i.e., $ ^{4}P_2=12 $ .