Laneka owns a cake shop. She is currently preparing cakes for two anniversary parties. The first cake has 3 small tiers and 1 medium tier and will serve a total of 100 guests. The second one has 3 small tiers and 2 medium tiers and will serve a total of 140 guests. Using the system, how many people would a medium tier feed and how many people would a small tier feed?

3s+m=100
3s+2m=140