I have this question on my study guide for an upcoming test. I reviewed the book and cannot find any example like it, if you can help, that would be great!
The monthly cost for cell phone usage, excluding taxes
and roaming charges, is $39.99 plus $0.40 for each daytime
minute used over 300 minutes. Find the monthly
cost for (a) 450 daytime minutes (b) m daytime
minutes.
2007-03-29 05:26:52 · 6 answers · asked by norcalgrl87 1 in Science & Mathematics ➔ Mathematics
a) = $39.99 + $0.4 * 150
= $99.99
b) if m>300
= $39.99 + $0.4 *(m - 300)
=$(0.4m - 80.01)
if not
= $39.99
2007-03-29 05:46:55 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Hi,
Your problem can be restated as a linear equation of the form, y = mx + b. In this case, the constant charge is $39.99 so that is the value of b. Because the other charge is $.40 PER MINUTE, that is the slope number that is multiplied times the number of minutes in excess of the first 300. So y = mx + b, become y = .40(x-300) + 39.99.
That is actually part of the answer to part b if we change the x to the m.
y = .40(m-300) + 39.99.<=This is part b
For part a, we will take our formula and substitute 450 for our variable, m.
y = .40(m-300) + 39.99.
y = .40(450-300) + 39.99.
y=.40(150)+39.99
y=60+39.99
y = 99.99
So 450 minutes on the phone cost $99.99
I hope that helps!
2007-03-29 12:36:12 · answer #2 · answered by Pi R Squared 7 · 0⤊ 0⤋
Gotcha buddy
a) Monthly cost = 39.99 + .4(150)
b) Monthly cost = 39.99 + .4(m-300) -> assuming you go over 300 minutes
a) the monthly cost is simply calculated by adding the base fee (39.99) and the product of overtime minutes * the rate (150*.4)
b) m = total daytime minutes used in a month. Assuming you go over 300 daytime minutes, simply plug in the number of minutes in for "m" and you got it
if you use less than or equal to 300 minutes, you just pay the base fee of 39.99
2007-03-29 12:42:48 · answer #3 · answered by dub554 1 · 0⤊ 0⤋
a) Cost = $39.99 + (450 - 300)(0.40) = $99.99
b) For m minutes,
if m<=300,
Cost = $39.99
if m> 300,
Cost = $39.99 + (m - 300)(0.40)
2007-03-29 12:38:12 · answer #4 · answered by MamaMia © 7 · 0⤊ 0⤋
Hmm. For part a, I'm pretty sure you can solved it on your own, right? For part b, it's just simple formation of algebric functions. For m daytime mins, the monthly cost will thus be $ [39.99 + 0.4(m - 300)] where m >/= to 300.
2007-03-29 12:36:01 · answer #5 · answered by Willy 2 · 0⤊ 0⤋
C= 39.99 +(450-300).4 = 39.99+60 = $99.99.
C = 39.99 if m=< 300
C= 39.99 + 4(m-300) if m >300
2007-03-29 12:41:09 · answer #6 · answered by ironduke8159 7 · 0⤊ 0⤋