Answer:
0.500 hour
Step-by-step explanation:
Givens
<em><u>Distance</u></em>
- Total Distance on the highway = 3hr * 60 miles / hr = 180 miles
- Distance in the city = 20 miles
- Total Distance = 180 + 20 = 200 miles
<em><u>Time</u></em>
- Time on the highway = 3 hours
- Time in the city = x
Formula
d /t = r
Solution
- Average rate = 57.14
- Total Distance / Total Time = average rate
- 200 / (3 + x) = 57.14 Multiply both sides by 3 + x
- 200 = 57.14 * (3 + x) Remove the brackets
- 200 = 57.14*3 + 57.14x Multiply the factors on the right
- 200 = 171.42 + 57.14x Subtract 171.42 from both sides.
- 200 - 171.42 = 171.42 - 171.42 + 57.14x So the subtraction
- 28.58 = 57.14x Divide by 57.14
- 28.57/57.14 = x
- x = 0.500 hour Answer
Strange question, as normally we would not calculate the "area of the tire." A tire has a cross-sectional area, true, but we don't know the outside radius of the tire when it's mounted on the wheel.
We could certainly calculate the area of a circle with radius 8 inches; it's
A = πr^2, or (here) A = π (8 in)^2 = 64π in^2.
The circumference of the wheel (of radius 8 in) is C = 2π*r, or 16π in.
The numerical difference between 64π and 16π is 48π; this makes no sense because we cannot compare area (in^2) to length (in).
If possible, discuss this situatio with your teacher.
