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.
