Answer:
525 sit-ups
Step-by-step explanatiSince there are 7 days in a week, and there are 3 weeks, you can multiply 7 * 3 = 21 to find out how many days Joe is doing situps. Next, you need to multiply the number of situps per day by the number of days: 25 * 21 = 525. Joe will do 525 situps in 3 weeks.
Hope this helps! :)
