Anna does sit-ups to get ready for her first triathlon. When she starts, she does a sit-up every 2 seconds. But, as she gets tired, each sit-up takes longer to do. Is the number of sit-ups Anna does proportional to the time she spends doing them?
Step-by-step explanation: proportional means corresponding in size or amount to something. However, the number of her sit-ups isn't consistent, so it isn't proportional to the time she spends doing them.