Problema Solution
Two sisters leave their house at the same time, and walk in opposite directions. In 5 hours they are exactly 30 miles apart. Find their speeds given that the older sister travels twice as fast as the younger?
Answer provided by our tutors
let
v = the speed of the younger sister
2v = the speed of the older sister (the older sister travels twice as fast as the younger)
t = 5 hr the time of the travel
d = 30 mi the distance between them
the distance = speed*time
since they travel in opposite directions the sum of their distances traveled is equal to the distance between them:
v*t + 2v*t = d
5v + 2v*5 = 30
by solving the equations we find
v = 2 mph
click here to see the step by step solution of the equation
2*2 = 4 mph
the speed of the younger sister is 2 mph.
the speed of the older sister is 4 mph.