Answer:
The least number of steps she takes to reach 20 m is 118 steps
Explanation:
For Laura, the length of a walking step = 50 cm = 0.5 m
The repeating number of steps she takes = Two steps forward one step backwards
The number of forward steps it would take for her to reach 20 m = (20 m)/(0.5 m) = 40 steps
Given that she always takes two steps forward and one step backwards, we have;
The number of steps forward every three steps = 2 step forward + (-1) step (backward)
The number of steps forward every three steps = 2 - 1 = 1 step forward
To reach 39 steps forward, she would need 39 × 3 = 117 steps
To get to the 40 steps she needs just a step forward, making the total number of steps to reach 40 steps = 117 + 1 = 118 steps
Therefore, the least number of steps she takes to reach 20 m = 118 steps.