Problema Solution

starting from the same position, Karen walked North at a rate of three kilometers per hour, and David walked East at a rate of 4 kilometers per hour. How far apart were they in two hours?

Answer provided by our tutors

since distance = speed*time we have


in 2 hours Karen will walk: 2*3 = 6 km


in 2 hours David will walk: 2*4 = 8 km


make a drawing of their path and notice that the distance d between them is the length of the hypotenuse of a right triangle with legs 6 km and 8 km


using the Pythagorean Theorem we can write:


d^2 = 6^2 + 8^2


d^2 = 100


d = 10 km


After 2 hours Karen and David are 10 km apart.