Question

.Admission to the movies costs $8 for adults and $4 for kids. The total bill for your entire extended family was $72. This scenario can be modeled by the equation 8a + 4k = 72. Which is not a possible combination of adults and kids?
A) 3 adults and 12 kids

B) 5 adults and 6 kids

C) 7 adults and 4 kids

D) 8 adults and 2 kids

Answer 1

Choice A says " 3 adults and 12 kids "

So that means a = 3, k = 12

Answer 2

Plug a = 3, k = 12 into the equation to get

8a + 4k = 72

8*3 + 4k = 72 ... replace 'a' with 3, since a = 3

8*3 + 4*12 = 72 ... replace k with 12, because k = 12

24 + 48 = 72

72 = 72 ... this equation is TRUE, so a = 3 and k = 12 both together form an ordered pair solution (3,12) to the equation 8a + 4k = 72

Answer 3

So "A) 3 adults and 12 kids " is a possible combination

That means we eliminate choice A because they ask " Which is NOT a possible combination of adults and kids?"

Answer 4

Hopefully you're seeing how this all works?