Alex stocks up for winter. He buys 36 cans of vegetables. He pays 80 cents per can for tomatoes and 40 cents per can for corn, for a total cost of $20.8. How many tomatoes does he buy?

Let tomatoes be as x and corn be as y.

Total cans is 36 cans.

$20.8 = 2080 cents

1. x + y = 36

2. 80x + 40y = 2080

From equation 1, we get

y = 36 - x

Substitute into equation 2,

80x + 40 (36 - x) = 2080

80x + 1440 - 40x = 2080

40x = 2080 - 1440

x = 640 : 40

x = 16

x + y = 36

16 + y = 36

y = 36 - 16

y = 20

Alex does buy 16 tomatoes.