Problem on Finding the Decimal Number

Topic : Decimal Number

Question : The base eight number 321 is equivalent to what decimal number

Solution :
321is the octal base
we have to convert it into decimal that is with base 10

So 321 = 3X8^2 + 2X8^1 + 1X8^0
= 3X64 + 16 + 1
= 192 + 16 + 1
= 209

So 321is 209 in decimal.