How do i find the dilation of a shape?

(note i put the graph in so plz )the graph shows the amount of water that remains in a barrel after it begins to leak. the variable x represents the number of days that have passed since the barrel was filled, and y represents the number of gallons of water that remain in the barrel. what is the slope of the line

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

Which value of y will make the inequality y< -1 false?