When going more than 38 miles per hour, the gas mileage of a certain car fits the model 4072-01-02-03-00_files/i0120000.jpg where x is the speed of the car in miles per hour and y is the miles per gallon of gasoline. Based on this model, at what speed will the car average 15 miles per gallon? (Round to nearest whole number.) a. 149 c. 48 b. 98 d. 73
y = 43.81 - .395x let y = 15....so we have
15 = 43.81 - .395x subtract 43.81 from both sides
-58.81 = -.395x divide both sides by -.395
x = about 149 mph
Answer:
d. 73
The car will average 15 miles per gallon at the speed 73 miles per hour
Step-by-step explanation:
Your equation is: y = 43.81 - 0.395x
We need to solve for x if y = 15
So plug 15 into your equation: 15 = 43.81 - 0.395x
Then rearrange your equation to get the variable by itself and change the sign: 0.395x = 43.81 - 15
Subtract 43.81 - 15 = 28.81
0.395x = 28.81
Then divide both sides of the equation by 0.395
0.395x/0.395 = 28.81/0.395
x = 72.9367088608
Then (Round to nearest whole number.)
Giving you your solution of 73
To Conclude:
The car will average 15 miles per gallon at the speed 73 miles per hour