Acircular pond 20m in diameter is surrounded by a gravel path 5m wide. the path is to be replaced by a brick walk costing $30 per square meter. how much will the walk cost?

Nick has box brads. he uses 4 brads for the first project. nick let’s b represent the original number of brads and finds that for the second project, the number of brads he uses is 8 more than half the difference of b and 4. write an expression to represent the number of brads he uses for the second project.