Problem A
Usually the number of bits in a byte is 8 or 16 or 32 and recently 64. You don't have to write a formula to restrict it to this number of bits. You are not asked to do so. The general formula is 2^n - 1 for the problem of Millie and her golden keys. Somehow the system can be made to choose the right number of bits. Apple IIe s for example, used 8 bits and there was a location that told the processor that fact.
2^n - 1 <<<<< Answer
Problem B
In this case n = 4
2^n - 1 = 2^4 - 1 = 16 - 1 = 15
Millie can collect 15 keys <<<<<< Answer
Answer: Option D
Step-by-step explanation:
The equation of a line in the form of "slope-interception" has the following form:

Where m is the slope of the line and b is the interception of the line with the y axis.
In this case we know that the line has a slope of -2. Then
.
We also know that the line intercepts the axis y at the point (0, 3) therefore we know that:
.
Finally the equation of the line will be:
If we add 2x on both sides of the equation we get:
The answer is the option D
ANSWER
l
Or
Or
EXPLANATION
The given line has slope,
and
We can find the equation in the point slope form, which is given by,
We substitute the point and slope to get,
We can also simplify further to get,
We make y the subject to get,
This is called the slope intercept form.
We could also write in standard form to get
Or
Total balance in Mr. Copley at the end of the month = $1473.61.
Initial deposite = $75 (not shown in his checkbook).
Let us assume his balance at the beginning of the month = x.
Total balance at the end of the month = The balance at the beginning of the month + total deposite.
$1473.61 = x + 75.
Subtracting 75 from both sides, we get
1473.61 -75 = x + 75 -75.
1398.61 = x.
Therefore, his balance at the beginning of the month was $1398.61.