1. The problem statement, all variables and given/known data Three truck drivers went into a roadside cafe. One truck driver purchased four sandwiches, a cup of coffee and ten doughnuts for $8.45. Another drivers purchased three sandwiches, a cup of coffee and seven doughnuts for $6.3. What did the third truck driver pay for a sandwich, a cup of coffee and a doughnut? 2. Relevant equations 3. The attempt at a solution The system's equations are: 4s + 1c + 10d = 8.45 3s + 1c + 7d = 6.3 1s + 1c + 1d = a The system has infinite solutions, right? There are 4 variables for 3 equations. I can't determine a.