I'm not sure whether there is a math hw thread and I'm quite too lazy to find it but the question is:
A rectangular dog pen with dimensions 10 feet by 5 feet is built right beside a river. A wooden deck of uniform width is going to be installed around the pen on the other three sides. The cost of building the wooden deck is $3 per square foot and the total cost for the project is $234. What is the width of the wooden deck? Include let statements.