PROBLEM 1-8-5

The distance between steps on a ladder is measured from the top of a step to the bottom of a higher step. If the distance between adjacent steps of my ladder is 25 cm, and each step is 2 cm thick, what is the distance between step 1 and step 7?

SOLUTION 1-8-5

From the top of a step to the top of a step above is 25 cm + 2 cm = 27 cm. From the top of step 1 to the top of step 6 is 5 times 27 = 135 cm. It's another 25 cm from the top of step 6 to the bottom of step 7. The distance from step 1 to step 7 is 135 cm + 25 cm = 160 cm.