Question

Let 5 digit numbers be constructed using the digits $0,2,3,4,7,9$ with repetition allowed, and are arranged in ascending order with serial numbers Then the serial number of the number 42923 is

Hint:

When constructing numbers with restricted digits, organize them systematically to calculate the serial number efficiently. Use counting principles like combinations and arrange them in ascending order to avoid missing any possibilities.

Answer 1

Correct Answer: 2997

Answer 2

\[ 2 + 3 + 4 + 6 + 6 = 1296 \] \[ 3 + 3 + 6 + 6 + 6 = 1296 \] \[ 40 + 6 + 6 = 216 \] \[ 420 + 6 = 36 \] \[ 422 + 6 = 36 \] \[ 423 + 6 = 36 \] \[ 424 + 6 = 36 \] \[ 427 + 6 = 36 \] \[ 429 + 6 = 6 \] \[ 429 + 20 = 6 \] \[ 429 22 = 1 \] \[ 429 23 = 1 \] \[ = 2997 \]