Yes -1 is a rational number. We can express it as a fraction of two whole numbers
One way is -1 = -1/1
The result of the fraction is 3.5
we can calculate this like this:

I think that the question is asking between which two natural numbers the result lies, and the result is 3 and 4: it's bigger than 3 and smaller than 4
Answer:
The expressions for the payment made to Mary are,
(Monday) 90 = 15m + b
(Tuesday) 62 = 8m + b
where m and b are the fee per student and the base fee, respectively. Solving for m and b, the values are 4 and 30.
The equation that represents Mary's earning is
y = 4x + 30
For 20 students,
y = 4(20) + 30 = 110
For Lisa's earnings,
y = 8x + 15
Substituting 20,
y =8(20) + 15 = 175
Thus, Lisa would earn more than Mary by $65.
(Btw this is not my work, I got it from someone else on brainly and wanted to help lol)
The rules of exponents tell you that you can distribute the exponent to each of the factors. When one already has an exponent, those exponents multiply.