20 - 200 = -180...negative
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.
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Step-by-step explanation:

For x=3, the denominator is equal to 0 and you can't divide by 0.
8x = 44 -4
8x = 40
x = 40/8
x = 5
Answer:
range= 10
median= 5
mode= 3
Variance= 11 (rounded) normal answer without rounding 10.809524
Midrange= 6