Step-by-step explanation:
Pythagoras :
c² = a² + b²
c is the Hypotenuse (side opposite of the right angle), which is in our case the distance of the 2 cars.
after 2 hours the east car was driving x miles. and the south car was driving x + 2×25 = x + 50 miles.
x² + (x + 50)² = 250²
x² + x² + 100x + 2,500 = 62,500
2x² + 100x = 60,000
x² + 50x = 30,000
x² + 50x - 30,000 = 0
the solution for a quadratic equation is
x = (-b ± sqrt(b² - 4ac))/(2a)
in our case
a = 1
b = 50
c = -30,000
x = (-50 ± sqrt(2500 - 4×1×-30000))/(2×1) =
= (-50 ± sqrt(2500 + 120000)/2 =
= (-50 ± sqrt(122500))/2 = (-50 ± 350)/2 =
= -25 ± 175
x1 = -25 + 175 = 150 miles
x2 = -25 - 175 = -200 miles.
negative distances don't make any sense here in our scenario, so the solution is x = 150 miles.
therefore, the east car was going 75 mph (traveled in 2 hours 150 miles).
and the south car was going 75 + 25 = 100 mph (traveled in 2 hours 200 miles).
