Aconcession stand sold a total of 138 small and large popcorns. a small popcorn costs $2.50, and a large popcorn costs $4.00. total popcorn sales were $466.50. how many large popcorns were sold?

X = small popcorns
y= large popcorns

x+y=138

2.50x + 4.00y= 466.50

y = 138-x

2.50x +4.00(138-x) = 466.50

2.50x +552-4x = 466.50

2.50x-4x = 466.50 - 552

-1.5x = -85.5

-1.5x/-1.5 = -85.5/-1.5

x = 57

Since ,

x+y=138

(57)+y = 138

y = 138 - 57

y = 81 

Therefore 81 large popcorns were sold!