Peter R. answered 12/01/22
Experienced Instructor in Prealgebra, Algebra I and II, SAT/ACT Math.
Here's yet another system of equations question. They all work pretty much in the same manner!
P = no. popcorn buckets; D = no. drinks.
Darren's cost is 3P + 2D = 21
Steve's cost is 2P + 4D = 22
Now need to decide to use substitution or elimination (or graph) method to solve.
I suggest elimination because 4 is a multiple of 2 (drink terms).
-2(3P + 2D = 21) becomes -6P - 4D = -42 for Darren
Steve is still 2P + 4D = 22
Adding: -4P = -20, so P = -20/-4 = $5
Substituting in the 1st original equation; 3(5) + 2D = 21 → 2D = 6 → D = $3
Let's see if that checks in the 2nd equation (Steve): 2(5) + 4(3) = 10 + 12 = $22 (OK)