in 1968, vehicle emmision standards allowed 6.3 hydrocarbons released per mile driven. By 1980, the standards allowed only .41 hydrocarbons released per mile driven. What was the rate of change from 1968 to 1980?

To calculate the rate of change from 1968 to 1980 in terms of hydrocarbon emissions, we need to determine the difference between the two emission standards and divide it by the number of years between these two dates.

The difference between the emission standards is given as 6.3 hydrocarbons per mile driven in 1968 and 0.41 hydrocarbons per mile driven in 1980.

To calculate the rate of change, we subtract the 1968 standard from the 1980 standard: 0.41 - 6.3 = -5.89.

Now we divide the difference by the number of years between 1968 and 1980, which is 12. So the rate of change would be -5.89 / 12 ≈ -0.49 hydrocarbons per mile driven per year.

Therefore, the rate of change in hydrocarbon emissions from 1968 to 1980 is approximately -0.49 hydrocarbons per mile driven per year. This indicates a reduction in hydrocarbon emissions over time according to the given standards.