A computer represents information in groups of 64 bits. How many different integers can be represented in BCD code?

Question

This from my Interview-MCQ module:

A computer represents information in groups of 64 bits. How many different integers can be represented in BCD code?

The given answer is 10¹⁶, however no explanation is provided, I was just wondering if somebody could help me understand the answer.

Answer 1

BCD is binary coded decimal. In BCD, every 4 bits is used to represent a single digit from 0 to 9. So if you have 64 bits, that gives you 64/4 = 16 decimal digits, which means you can have 10^16 different integers.