Let x = # of persons. The formula for Hamilton's cost is 15x dollars. The formula for Turaskis' cost is 50 + 10x dollars. Hamilton is cheaper if and only if 15x < 50 + 10x Simplify and solve 15x - 10x < 50 5x < 50 x < 50/5 = 10. Answer. Hamilton is cheaper than Turaskis if and only if the number of peop[le is LESS than 10.