Marco and his dad went strawberry picking. Together they collected strawberries that weighed 42 pounds. On the way back Marco lost 18 pounds of strawberries. Marco's strawberries now weighed 3 pounds. How much did his dad's strawberries weigh?
1. Marco and his dad went strawberry picking. Together they collected strawberries that weighed 42 pounds.

2. On the way back Marco lost 18 pounds of strawberries.

3. Marco's strawberries now weighed 3 pounds.

4. How much did his dad's strawberries weigh?

We can use algebra to solve this problem. Let's set up an equation:

Marco's strawberries + Dad's strawberries = 42 pounds

Marco's strawberries = 3 pounds

Dad's strawberries = 42 - 3

Dad's strawberries = 39 pounds