The cost for a long-distance telephone call is $0.36 for the first minute and $0.21 for each additional minute or portion thereof. Write an inequality representing the number of minutes a person could talk without exceeding $3.
2006-07-25 17:57:49 · 7 answers · asked by sistermoon 4 in Education & Reference ➔ Homework Help
0.36+0.21(x) < 3
where 1+x = the number of minutes
Or rewriten as 0.36+0.21(x-1)<3
2006-07-25 18:02:01 · answer #1 · answered by Beau 2 · 1⤊ 0⤋
The first step in writing an equation or inequality is to define your variable (or variables). Let x stand for the length of the phone call, with the number rounded up to the nearest whole minute. First I will write an equation for the cost of a call:
c = 0.36 + 0.21(x-1)
Why do we use (x-1) instead of just x? Well, suppose you make a 1 minute phone call; you should just be charged 36 cents.
By subtracting 1 from the number of minutes, we make sure that you aren't charged twice for the first minute.
Now it's easy to turn this into an inequality:
0.36+.21(x-1) < 3
If you solve for x, you will get x < 13.57...
Because of how we are being charged, you can actually only afford 13 minutes. If you go slightly over 13 minutes, that is rounded to 14 and the price surpasses $3.00.
P.S., Sometimes people use the symbol [x] to mean that we should round up first.
2006-07-26 01:21:44 · answer #2 · answered by stevenatasu 1 · 0⤊ 0⤋
If N is the number of minutes then
0.36 + 0.21*(N-1) <3
2006-07-26 01:02:46 · answer #3 · answered by mityaj 3 · 0⤊ 0⤋
0.36+0.21 * (x-1)<3 where x is the no. of minutes talked rounded off to the next higher integer :-) (mityaj is quite right except for the rounding off part)
2006-07-26 01:09:38 · answer #4 · answered by Payal G 2 · 0⤊ 0⤋
13 minutes
why?
0.36 +0.21(x-1)=3
solve for x
x = 13.57
therefore should be just 13 minutes!
2006-07-26 01:43:49 · answer #5 · answered by alandicho 5 · 0⤊ 0⤋
a person can talk for 6 minutes without going over $3.
2006-07-26 01:05:17 · answer #6 · answered by Izzy L 2 · 0⤊ 1⤋
x(0.21) + 0.36 = $3.00
2006-07-26 01:02:14 · answer #7 · answered by woman38 5 · 0⤊ 0⤋