Linear Inequalities

Question

Desiree and Mario together have $30. Mario and Scott together have $26. Desiree and Scott together have $34. What is the least amount of money any of them has

 

Answer 1

Write three equations: D+M - 30; M+S = 26; D+S = 34.

 

Solve that 3 by 3 systems (I prefer RREF operation on the augmented matrix, using my old TI-83 calculator).

Alternatively, use determinants.

 

I get D=19, M=11, S=15. Check these results. Then you can answer the question.

 

These equations should have occurred to you!