9. Mystery Weight
Continuing with a problem number 9 on our list of math problem-solving activities for middle school – when three girls jumped on a weighing scale together, it read 360 pounds. One girl stepped off and the scale moved down to 230 pounds. One more girl jumped off and the scale read 120 pounds. What was each girl’s weight?
Here, a simple working backward strategy will be effective in distinguishing each girl’s weight.