Calculate the speed of a person who walked 100 m in 25 seconds. Show all of your work. Step 1: Using a light color, highlight the information the problem gives you. (numbers & units) Step 2: Write down the formula you will use to calculate the speed. You can copy it from above. 100 m in 25 seconds. Step 3: Plug the numbers in the problem into the formula. Step 4: Divide the top number by the bottom number, and write your final answer with the correct units.