A service technician charges $46.25 for 5 hours of work and $75.25 for 9 hours or work. Assuming a linear relationship between the charge and the number of hours worked, what will be the charge for 15 hours of work?
2006-11-06 09:03:27 · 5 answers · asked by anonymous91 1 in Science & Mathematics ➔ Mathematics
For 4 additional hours of work, the cost went up $75.25 - $46.25 = $29, which is $29/4 = $7.25/hr. To go up 10 hours from 5 to 15 should therefore cost an extra $72.50, which added to the original $46.25 is $118.75.
2006-11-06 09:06:07 · answer #1 · answered by DavidK93 7 · 1⤊ 0⤋
The equation for a staight line is y = mx+b where m = slope and b = the y intercept. In this case x = hours and y = total cost. First, find the slope.
m = (y2-y1) / (x2-x1) = (75.25- 46.25) / (9-5) = 7.25 dollars per hour
Now the y-intercept: use either point... 46.25 = (7.25 * 5) + b
solve for b: b= 10
Now solve for y when x = 15 hours:
y = (7.25 * 15) + 10 = $118.75
2006-11-06 17:20:53 · answer #2 · answered by Anonymous · 1⤊ 0⤋
According to the numbers you provided,
for 5 hours of work, hourly charge (aka slope) = 46.25/5 = 9.25
for 9 hours of work, hourly charge (aka slope) = 75.25/9 = 8.36
These are two different slopes. That is not a linear relationshiop between the charge and hours of work..
2006-11-06 17:10:03 · answer #3 · answered by Kushan T 1 · 0⤊ 0⤋
(5,46.25) and (9,75.25)
m = (75.25 - 46.25)/(9 - 5)
m = (29/4)
(5,46.25), m = (29/4)
46.25 = 5(29/4) + b
46.25 = (145/4) + b
185 = 145 + 4b
4b = 40
b = 10
y = 7.25x + 10
y = 7.25(15) + 10
y = 108.75 + 10
y = 118.75
ANS : 15 hours will cost you $118.75
2006-11-06 18:57:56 · answer #4 · answered by Sherman81 6 · 0⤊ 0⤋
The hourly rate would be $7.25, for a total of $118.75 for 15 hours work.
2006-11-06 17:12:30 · answer #5 · answered by Racewalking Invicta Swami 4 · 0⤊ 0⤋