The number of Hybrid vehicles sold weekly at a local car lot increased from 11 in 2006 to 19 in 2008. Predict the number of Hybrid vehicles sold weekly in 2011.
My answer:
rate = 19 - 11
2008 - 2006
rate = 8
2
rate = 4
then I subtracted 2011 from 2008 got 3 and multiplied that by 4 to get
12 as the # of cars a wk per yr. increase. Is this right?
You really should write a linear equation:
You're right on calculating the rate. It is 4. You can also call that the slope of the line. In y=mx+b form,
y=4x+b Since you started at 11 in 2006, 11 is your y-intercept (b)
y=4x+11
Again, since you started at 2006, 2011 is 5 years from that so plug in 5 for x.
y=4*5+11=31.
Does this make sense or did you not start linear equations yet??
To predict the number of Hybrid vehicles sold weekly in 2011, you can use the concept of a linear rate of change.
First, find the rate of change or the average increase in the number of Hybrid vehicles sold per year:
rate = (number of vehicles in 2008 - number of vehicles in 2006) / (year in 2008 - year in 2006)
= (19 - 11) / (2008 - 2006)
= 8 / 2
= 4
This means that on average, there was an increase of 4 Hybrid vehicles sold each year between 2006 and 2008.
Next, calculate the difference in years between 2011 and 2008:
difference in years = 2011 - 2008
= 3
Finally, multiply the rate of change by the difference in years to predict the number of Hybrid vehicles sold in 2011:
predicted number of vehicles in 2011 = rate * difference in years
= 4 * 3
= 12
Therefore, based on the average rate of change, it is predicted that there will be 12 Hybrid vehicles sold weekly in 2011.