The height of the pedals of a bicycle change with respect to time. The minimum height recorded for the pedals was 21 cm above the ground, and the maximum height was 59 cm. Assume that the bicycle is peddled at the rate of 3 cycles in 60 seconds, and that the pedal starts at its lowest possible position. When during the first 30 seconds of riding is the pedal more than 30.5 cm above the ground?

4 answers

this is just like the tide problem. See what you can do.
What tide problem?
https://www.jiskha.com/questions/1508530/3-at-the-end-of-a-dock-high-tide-of-14-m-is-recorded-at-9-00-a-m-low-tide-of-6-m-is
https://www.jiskha.com/questions/1829521/the-water-level-in-a-lake-rises-and-falls-throughout-the-day-the-average-depth-of-the