Problema Solution
Anna went from home to school with the speed 3 km/hour. She ran back home with the speed 6 km/hour.Her sister Olga went to school and back with the same speed, and she spent as much time on the road as Anna. What was Olga's speed?
Answer provided by our tutors
Let
v = Olga's speed
t = the time Anna spent going to school with speed of 3 km/hour
t/2 = the time Anna spent running back home with speed of 6 km/hour (since she run with double speed she spent half the time that she spent going to school)
t + t/2 = 3t/2 is the total time
Since distance = speed*time and the both made the same distance we can write:
3t + 6*(t/2) = (3t/2)*v
6t = (3/2)tv divide both sides by t
(3/2)v = 6
v = 2*6/3
v = 4 km/hour
Olga's speed was 4 km/hour.