long-distance calls from New York to Harare are priced at 85 cents/min off peak and $1.20/min at peak times.
a_ draw, on the same exes, conversion graphs for the two different rates.
b_ from your graph estimate the cost of an 8 minute call made off peak.
c_ estimate the cost of the same call made at peak rate.
d_a call is to be made from a telephone box. if the caller has only $4 to spend, estimate how much more time he can talk for if he rings at off speak instead of at peak times
At off peak rate:
cost = .85t
at peak time rate:
cost = 1.2t
I can't do the graphs for you, but I suggest for the first you use:
(0,0) and (20, 17) to sketch the first graph, and
(0,0) and (20, 24) for the second one
sub t = 8 into off-peak equation
and into the peak equation to check your estimated costs
for the last part go up to 4 on the vertical axis and run horizontal till you meet the lines.
or
to get the actual answers .....
4 = .85t
t = 4/.85 = appr 4.7 minutes
4 = 1.2t
t = 4/1.2 = 3 1/3 minutes
a) To draw the conversion graphs for the different rates, we will use the x-axis to represent the time in minutes and the y-axis to represent the cost in dollars.
For the off-peak rate of 85 cents/min, the graph will have a slope of 0.85 and will start from the origin (0, 0). The equation for this line would be: y = 0.85x.
For the peak rate of $1.20/min, the graph will have a slope of 1.20 and will also start from the origin. The equation for this line would be: y = 1.20x.
b) To estimate the cost of an 8-minute call made off peak, we can refer to the graph for the off-peak rate. Since the slope is 0.85, we can multiply the number of minutes (8) by this rate to find the cost: y = 0.85 * 8 = $6.80.
c) To estimate the cost of the same 8-minute call made at the peak rate, we refer to the graph for the peak rate. Multiplying the number of minutes (8) by the peak rate of $1.20 will give us the cost: y = 1.20 * 8 = $9.60.
d) To estimate how much more time the caller can talk for if they spend $4 at off-peak instead of at peak times, we need to find the number of minutes that can be bought with $4 at each rate.
For the off-peak rate, we divide the available dollars ($4) by the cost per minute (0.85 cents): minutes = $4 / $0.85 = 4.71 minutes.
For the peak rate, we divide the available dollars ($4) by the cost per minute ($1.20): minutes = $4 / $1.20 = 3.33 minutes.
Therefore, by ringing at off-peak times instead of peak times with $4, the caller can talk for approximately 1.38 minutes (4.71 - 3.33 minutes) more.