Under her cell phone plan, Micaela pays a flat cost of $47.50 per month and $4 per gigabyte, or part of a gigabyte. (For example, if she used 2.3 gigabytes, she would have to pay for 3 whole gigabytes.) She wants to keep her bill under $55 per month. What is the maximum whole number of gigabytes of data she can use while staying within her budget?

Answer 1

Let's assume Micaela uses x gigabytes of data.
The cost of the data usage is 4x dollars.
The total cost including the flat cost for the plan is 47.50 + 4x dollars.
According to the condition, this total cost should be less than $55.
So, we have the inequality:
47.50 + 4x < 55
Subtracting 47.50 from both sides, we get:
4x < 55 - 47.50
4x < 7.5
Dividing both sides by 4, we get:
x < 7.5/4
x < 1.875
Since Micaela needs to pay for whole gigabytes of data, the maximum whole number of gigabytes she can use while staying within her budget is $\boxed{1}$.