We know that
• There are 40 children.
,
• Hamburgers cost $5 each.
,
• Hotdogs cost $3 each.
,
• The total cost of hotdogs and hamburgers was $150.
Let's call x hamburgers and y hotdogs. The total number of hotdogs and hamburgers is represented by the following equation.
The total cost is represented by the following equation.
Let's multiply the first equation by -3.
Then, we combine it with the second equation.
Now we use the x-value to find y.
Therefore, there were purchased 15 hamburgers and 25 hotdogs.