Math problem involving cost

Question

It costs three times as much to build a desk as it does to build a chair. It the total cost of building one desk and one chair is $220, how much does it cost to build each?

Answer 1

First - Set up your variables

• Let D=cost of desk
• Let C=cost of chair
• D=3C

Second - Translate general equation from English to math

• The cost of building one desk and one chair is $220
• 3C+C=220

Third - Solve equation to find the cost of a chair

• 3C+C=220
• 4C=220
• C=55

Finally - Use the cost of the chair to find the cost of the desk

• (Cost of Desk)+(Cost of Chair)=$220
• (Cost of Desk)+55=220
• Cost of Desk = 165