Hands-on math!

Washington State Math Olympiad
Hints and Solutions
2017 Grade 7 Measurement
Problem

1) It takes 4 workers 5 hours to build 6 structures. At this rate, how long will it take 2 workers to build 9 structures?

2) A coat is priced at $155. In January, the style seems popular so the store raises the price by 20%. Unfortunately, the coat does not sell at that price. In April, the price is reduced by 20%. What is the price of the coat after this?

3) A rectangular box has a surface area of 94 square inches and a volume of 60 cubic inches. A new box is made that is a scaled up version of this original box. The new box has a surface area of 376 square inches. What is the volume of the new box?

Problem

4) Celena is traveling home from a friend's house. She starts on her bike and travels 12 miles per hour for 5 miles. After getting a flat tire, she walks and pushes her bike 1⁄2 mile for 1⁄4 hour. Then her dad picks her up and drives the remaining 6 miles home at 18 miles per hour. What is Celena's average speed for the whole trip?

5) Ayomide is buying fancy napkins for his restaurant. The Pantry sells 1300 napkins for $160.81. K Supplies sells 241 napkins for $29.76, and Target charges $18.57 for 150 napkins. Which is the better buy?