The relation between a and s is given to be:
a = 640s
where,
a = number of acres
s = number of square miles
We are to find the number of acres for 7.5 square miles.
This means, s = 7.5
Using the value in the formula, we get:
a = 640 x 7.5 = 4800 acres
So the answer to this question is option B
