Question

Which of the following is NOT an octal number?19,77,15,101

Answer 1

the number which is not an octal number is
15

Answer 2

19 is NOT an octal number.

1. An octal number uses the digits from 0 to 7 and has a base of eight.

2. From the given numbers, only 19 contains a digit greater than 7, i.e. 9. The rest of the digits have numbers from 0 to 7.

3. Hence, 19 is NOT an octal number.