For this case, the first thing we must do is define variables. We have then: x: number of nickels y: number of dimes We write the system of equations that adapts to the problem. We have then: 0.05x + 0.10y = 6.10 x + y = 67 Solving the system we have: x = 12 y = 55 Answer: there are 12 nickels Question 2: For this case, the first thing we must do is define variables. We have then: x: Allan's score y: Dave's score We write the system of equations that adapts to the problem. We have then: x + y = 375 x = 2y-60 Solving the system we have: x = 230 y = 145 Answer: Dave: 145 Allan: 230