Final answer:
The cost of one hot dog is $1.
Step-by-step explanation:
To find the cost of one hot dog, we can set up an equation based on the given information. Let x be the cost of one hot dog. Jacob buys 3 hot dogs and a $1 soda, so his total expense is 3x + 1.
Marlena buys 2 hot dogs and a $2 soda, so her total expense is 2x + 2. Since they spent the same amount, we can set up the equation: 3x + 1 = 2x + 2. Solving this equation, we find that x = $1.