Question

A ski club with 28 members went on a ski trip. some members rented skis and the rest rented snowboards. if skis rent for $16.00 a day and snowboards rent for $19.00 a day, and the club spent 478.00 in rentals, how many ski club members rented skis?

Answer 1

$there \ are \ 28 \ members \\ the \ number \ of \ members \ renting \ skis - x\\the \ number \ of \ members \ renting \ snowboards - y\\skis \ rent \ for \ \ 16.00 \ a \ day \ and \ snowboards \ rent \ for \ \ 19.00 \ a \ day\\\\\begin{cases} x+y=28 \ \ / \cdot (-16) \\ 16x+19y = 478 \end{cases}$

$\begin{cases} -16x-16y=-448 \\ 16x+19y = 478 \end{cases}\\+ -------\\3y=30 \ \ / :3 \\y=10 \\ \\ x+y=28\\x+10=28\\x=28-10\\x=18 \\ \\ Answer: \ 18 \ members \ rented \ skis .$