Members of the student council are selling T-shirts. The number of T-shirts sold and the amount of money collected each day is shown in this table. T-shirt Sales Day T-Shirts Sold Amount Collected Monday 12 $180 Tuesday 15 $225 Wednesday 21 $315 Thursday 17 $255 Write an equation that can be used to determine the amount of money collected, m, in dollars, for the number of T-shirts sold, s.​