Question

Your cell phone plan charges a base charge each month plus a charge per daytime minute of usage and December used 510 daytime minutes and your bill was 92.25 in January you only use 397 daytimes minutes and your bill was 77.56 in February your bill was 80.9 for how many daytime minute did you use in February

Answer 1

Answer:

In February, 423 daytime minutes is used

Step-by-step explanation:

Let the base plan charges be x

And cost per daytime minute be y

In December,

x  + 510y =  92.25------------------(1)

In January,

x + 397y = 77.56---------------------(2)

Subtracting eq(2) from eq(1)

x  + 510y =  92.25

x + 397y = 77.56

-------------------------------

0  + 113y = 14.69

-------------------------------

y = \frac{14.69}{113}

y =  0.13----------------------------------(3)

Substituting (3) in (1)

x  + 510(0.13) =  92.25

x + 66.3 = 92.25

x = 92.25 - 66.3

x = 25.95

So In February

base plan  + (daytime minute)(cost per daytime minute) = 80.9

25.95 + (daytime minute)(0.13) = 80.9

(daytime minute)(0.13) = 80.9 - 25.95

(daytime minute)(0.13) = 54.95

(daytime minute) =$\frac{54.95}{0.13}$

daytime minutes = 422.69

daytime minute  $\approx 423$