4x Find the average rate of change between t=1 and t=2 A 16feet/second B 8feet/second C -8feet/second

To find the average rate of change of a function between two points, we need to calculate the difference in the function values at those points and divide it by the difference in the independent variable values.<br /><br />In this case, we are given the function $4x$ and we need to find the average rate of change between $t=1$ and $t=2$.<br /><br />The function value at $t=1$ is $4(1) = 4$.<br />The function value at $t=2$ is $4(2) = 8$.<br /><br />The difference in the function values is $8 - 4 = 4$.<br />The difference in the independent variable values is $2 - 1 = 1$.<br /><br />Therefore, the average rate of change between $t=1$ and $t=2$ is $\frac{4}{1} = 4$.<br /><br />So, the correct answer is B) $8feet/second$.