Question

what is the average time for the toy car to move 1.0 m on dirt?
20.2 s
24.4 s
28.1 s
60.7 s
time for toy car to travel 1.0 m on different surfaces
surface time (s) trial 1 time (s) trial 2 time (s) trial 3
dirt 20.0 19.2 21.5
tile 29.1 26.7 28.5
cement 25.5 23.4 24.2

Explanation:

Step1: Recall average formula

The formula for the average (mean) of a set of numbers is $\bar{x}=\frac{\sum_{i = 1}^{n}x_{i}}{n}$, where $x_{i}$ are the individual values and $n$ is the number of values. Here, for the dirt - surface trials, $n = 3$, $x_1=20.0$, $x_2 = 19.2$, and $x_3=21.5$.

Step2: Calculate the sum

$\sum_{i=1}^{3}x_{i}=20.0 + 19.2+21.5=60.7$.

Step3: Calculate the average

$\bar{x}=\frac{60.7}{3}\approx20.2$.

Answer:

20.2 s