Let h = hot dog Let s = soft drink 4h + s = 6.30...Equation A h + 4s = 4.20...Equation B
We have two equations in two unknowns. The unknowns are the variables h and s. I will solve for s in Equation A by subtracting 4h from both sides. s = -4h + 6.30 I will now replace s in Equation B with -4h + 6.30 to find the price of one hot dog. h + 4(-4h + 6.30) = 4.20 h -16h + 25.2 = 4.20 -15h = -25.2 + 4.20 -15h = -21 Divide both sides by -15. h = -21/-15 h = 21/15 h = 7/5 h = $1.40 We now know the value of one hot dog. Go back to EITHER Equation A or B, replace h with 1.40, do the algebra and you will find the price of one soft drink.
