how many cones were sold?

Question

At an ice cream parlor, ice cream cones are $1.10 and sundaes are $2.35. One day the receipt for a total of 172 cones and sundaes were $294.20. How many cones were sold? 

Answer 1

C = number of cones sold

S = number of sundaes sold

C + S = 172      C = 172 - S

$1.10C + $2.35S = $294.20        $1.10(172 - S) + 2.35S = $294.20        -$1.10S + 2.35S = $105.00   1.25S = $105.00

                                                  $189.20 - $1.10S + 2.35S = $294.20                                      1.25S/1.25=$105/1.25

                                                 -$189.20                             -$189.20                                                    S = 84

                                                                                                                                                       C = 172 - S

                                                                                                                                                       C = 172 - 84

                                                                                                                                                       C = 88