Question 1207807
A Dodge Neon and a Mack truck leave an intersection at the same time.The Neon heads east at an average speed of 30 miles per hour, while the truck heads south at an average speed of 40 miles per hour. Find an expression for their distance apart d (in miles) at the end of t hours.

Let x(t): the distance the Neon has traveled east after t hours  , speed = 30 mph
and y(t): the distance the truck has traveled south after t hours, speed 40 mph

x(t) =30t
y(t)=40t

d(t) = sqrt((30t)^2+(40t)^2)  ( Pythagoras theorem)

d(t) = sqrt(900t^2+1600t^2)

d(t) = sqrt(2500t)

d(t) = 50t  is the required expression