Question

12. How many numbers, each less than 400 can be formed with the digits 1, 2, 3, 4, 5, 6 if
repetition of digits is allowed ?​

Answer 1

Answer:

12,13,23,31,21,41,14,51,56,65,61,64,62,6336,45

so much digit can form

Answer 2

Answer:

Numbers less than 400 can be formed with the digits 1, 2, 3, 4, 5, 6 and

repetition of digits is allowed  so digit should be taken at Hundred place would be 1,2,3.

⇒I case :-  3 a b

now a can take all six values , similarly b can also all xix values

so total number of ways = 6*6 = 36 ways

⇒II case :-  2 a b

now a can take all six values , similarly b can also all six values

so total number of ways = 6*6 = 36 ways

⇒III case :-  1 a b

now a can take all six values , similarly b can also all six values

so total number of ways = 6*6 = 36 ways

Total numbers formed = 36+36+36 = 108