If someone sells 271 bags of popcorn and made 447 dollars, with a large bag costing 3 dollars and a small one costing 1 dollar. How many bags did they sell?

Number of small bags = x

Number of large bags = y

x + 3y = 447

x + y = 271

Subtract the second equation from the first to get

2y = 176

y = 88

x = 183

I'm assuming you meant to say 'How many small/large bags did they sell?'

So

183 small bags and 88 large bags

expression #3 is not equivalent. the others are.

ok then what happened.