Question

You and a friend go to super taco for lunch. You order three soft tacos and three burritos and your bill totals $11.25. Your friends bill is $10.00 for four soft tacos and two burritos. How much do soft tacos and burritos cost? Let s equal the cost of a soft taco and b equal the cost of a burrito.

Answer 1

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.

Answer 2

Soft tacos are going to be $1.25, and burritos are going to be $2.50