1.8m = 7$3m = 10$5m = 15$10m = 25$15m = 38$
3m = 5$5m = 7$10m = 10$20m = 15$30m = 20$40m = 30$
1m = 3$3m = 5$5m = 7$10m = 11$15m = 13$20m = 15$