After selling 72 articles a man earns a profit equals to cost price of 9 articles. Find the profit %.

\(15\frac{2 }{7}\)% \(13\frac{2 }{5}\)% \(12\frac{1 }{2}\)% \(10\frac{1 }{5}\)%

\(12\frac{1 }{2}\)%

ATQ,             72S - 72C = 9C                      72S = 81C                       8S = 9C                      \(\frac{s}{c}\)  = \(\frac{9}{8}\)              Profit % = \(\frac{1}{8}\) × 100 = 12\(\frac{1}{2}\)%