Answer:
There are 9 pizza rolls and 12 mini hotdogs in the meal.
Step-by-step explanation:
We are given the following in the question.
Let x be the number of pizza rolls sold and y be the number of mini hotdogs in the combination meal.
Total number of items in combination meal = 21
Thus, we can write the equation:
![x + y = 21](https://tex.z-dn.net/?f=x%20%2B%20y%20%3D%2021)
Calorie in a pizza roll = 60
Calorie in a mini hotdog = 70
Total calories = 1380
Thus, we can write the equation:
![60x + 70y = 1380](https://tex.z-dn.net/?f=60x%20%2B%2070y%20%3D%201380)
Solving the two equations, we get,
![60x + 70y - (60x+60y) = 1380 - 60(21) \\10y = 120\\\Rightarrow y = 12\\\Rightarrow x = 21-12 = 9](https://tex.z-dn.net/?f=60x%20%2B%2070y%20-%20%2860x%2B60y%29%20%3D%201380%20-%2060%2821%29%20%5C%5C10y%20%3D%20120%5C%5C%5CRightarrow%20y%20%3D%2012%5C%5C%5CRightarrow%20x%20%3D%2021-12%20%3D%209)
Thus, there are 9 pizza rolls and 12 mini hotdogs in the meal.