Which rate can you set 7 miles/1 hour equal to in order to find the distance traveled in 49 hours at 7 miles per hour?

Using the graph below, select all statements that are true. a. f(0.6)=0 b. f(-3.2)=-3 c. f(5.1)=5 d. this is the graph of the greatest integer function. e. this graph is one-to-one.

Anyone know? will mark brainliest if correct

If 10 men take 18 days to mow 60 acres of grass, how long will 15 men take to mow 80 acres?