1. Determine the total time Chris worked on Saturday:
- She started at 9 a.m. and finished at 6 p.m.
- From 9 a.m. to 6 p.m. is 9 hours.
2. Calculate the time spent washing, waxing, and vacuuming the cars:
- She did 3 cars, and each took 1.5 hours.
- Total time for cars: 3 × 1.5 = 4.5 hours.
3. Calculate the time spent washing windows:
- She spent 3 hours washing windows.
4. Add the time spent on cars and windows:
- 4.5 hours (cars) + 3 hours (windows) = 7.5 hours.
5. Subtract this from the total work time to find the time spent mowing:
- 9 hours (total) - 7.5 hours (cars and windows) = 1.5 hours.
6. Convert hours to minutes:
- 1.5 hours × 60 minutes/hour = 90 minutes.
Answer: 90 minutes.
Parent Tip: Review the logic above to help your child master the concept of 5th grade math word problems.
