Question

How many different three-digit numbers less than 300 can be formed with the digits 1, 2, 3, and 5 if repetition of digits is allowed?​

Answer 1

Answer:

note : every place have 4 chance of arrangement because repetition of number is allowed...

for 3 digit number :

_ _ _ first place have 2 number (1/2) = 2!

second place = 4

third palce = 4

Answer = 4×4×2 =32

for two digit number :

_ _ 4 × 4 = 16

for one digit number :

_ 4P1 =4

Answer = 32+16+4 = 52

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