Question

How may four distinct digit numbers can be made out of the digits 1, 2, 3 and 9 which are less than 3000, repetition of the digits being permitted?

Answer 1

Please see the attachment

Answer 2

Answer:

128

Step-by-step explanation:

Number is a 4 digit number

Number of choices for first digit (Thousands place) = 2

That is 1 and 2

Number of choices for second digit (Hundreds place) = 4

That is 1, 2, 3 or 9

Number of choices for Third digit (Tens place) = 4

That is 1, 2, 3 or 9

Number of choices for Fourth digit (Ones place) = 4

That is 1, 2, 3 or 9

Number of combinations = 2 x 4 x 4 x 4 = 128

Answer: There are 128 combinations.