Alisa has a stride of 0.5 a metre. If she travels by walking 2 steps forward and one step back, What is the least number of steps she needs to reach a spot of 20 metres? BTW answer is not 120 m
naturally the number of steps will not be measured in meters.
Each 3 steps, she advances 0.5 meters (0.5+0.5-0.5)
So, after 2*3*19 = 114 steps, she has advanced 19 meters.
On the 116th step she has gone the last meter, and does not need to step back again.