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By your cell phone contract, you pay a monthly fee plus some money for each minu

ID: 3041409 • Letter: B

Question

By your cell phone contract, you pay a monthly fee plus some money for each minute you use the phone during the month. In one month, you spent 300 minutes on the phone, and paid $25.50. In another month, you spent 330 minutes on ther phone and paid $26.55

Let x be the number of minutes you talk over the phone in a month, and let y be your cell hpone bill for the month. Use a linear equation to model your monthly bill based on the number of minutes you talk over the phone

A) This linear model's slope-intercept equation is....

b) If you spent 200 minutes over the phone in a month, you would pay....

C) if in a month, you paid $29.70 of cell phone bill, you must have spent.... minutes on the phone in that month

Explanation / Answer

y = x*a+b

Where a is the bill per minute and b is the monthly fees

Equation 1

25.5 = 300a+b

Equation 2

26.55 = 330a+b

Equation 1 and 2

30a = 1.05

a = $0.035

b = $15

A)

y = 0.035*x+15

b)

y = 0.035*200+15 = $22

c)

y = 29.7

x= (29.7-15)/0.035

x = 420 minutes