Answer:85
Explanation:
In Binary, we have 8 bits, all powers of 2, going up to 128.
When you only have 7 digits, you just add 0's to the left until it's 8. So in this case it would 01010101. Each 0 means the bit is "off," and each 1 means the bit is "on."
The 1st bit, from left to right, equals 128. The next is 64, then 32, then 16, then 8, then 4, then 2, then 1.
Since this specific number is alternating between bits, we know it is:
64 + 16 + 4 + 1 = 85
Since these are the bits that are turned on. Hope this helps!