3 and 1 eighths of the yard still needs to be mowed.<span />
You sum two vectors by summing the correspondent coordinates:

So, you have

This is a mistake, there is no shading like there is supposed to be, tell your teacher she will understand that this page got printed wrongly
Answer:
20.4
Step-by-step explanation:
If you are using D = r × t
10.2 = 0.5(t)
10.2/0.5 = t
20.4 = t