Answer
$d=50 t mph$
Work Step by Step
Observe that the car is running on east while the truck is running on South. Then, we have:
$s_{mc}=30 mph$
$s_{mt}=40 mph$
By the Pythagorean Theorem, according to The figure, we get:
$d^2=(30.t)^2+(40.t)^2$
Using the property of power
$d^2=900.t^2+1600.t^2$
$d^2 = 2500.t^2$
Extracting the square root in both sides:
$d=\sqrt{2500.t^2}$
Property of radicals say:
$d=\sqrt{2500}.\sqrt{t^2}$
$d=50.t mph$
