If two hamburger and one soda cost $6 and one hamburger and two sodas cost $4.50, find the cost of one hamburger and one soda.

One hamburger and one soda would cost $3.50.

Because one hamburger costs $2.50, and one soda costs $1.00.

And if two hamburgers and one soda costs $6.00, 2x$2.50 (Hamburgers) = $5+$1 (Soda) = $6. One hamburger and two sodas costs $4.50. 2x$1.00 (Soda) = $2.00+$2.50=$4.50.