Four soft tacos and two burritos for $10 is represented by 4s + 2b = $10.
Three soft tacos and three burritos for $11.25 3s + 3 b = $11.25
... where s and b are the unit costs of the tacos and burritos respectively.
Solve this system of linear equations for s and b:
Mult the first equation by 3: 12s + 6b = $30
Mult the 2nd eqn by -4: -12s -12b = -$45
Combine these equations: -----------------------------
-6b = - $15
Solve for b b = $15/6, or $2.50 per burrito
Subst. this $2.50 into 4s + 2b = $10 to find s:
4s + 2($2.50) = $10, or 4s + $5 = $10. Then s = $5/4 = $1.25 per soft taco.
