Question

4 chicken pastries & 5 beef pastries cost $42. 2 chicken pastries & 2 beef pastries cost $20. How much does a beef pastry cost?

Answer 1

[AI-generated answer — Bot GPT 3.5]

Let the price of a chicken pastry be C and the price of a beef pastry be B.

From the problem we can create two equations:
4C + 5B = 42 (1)
2C + 2B = 20 (2)
Multiply equation (2) by 2 to isolate the number of chicken pastries: 4C + 4B = 40 (3)
Subtract equation (3) from equation (1): (4C + 5B) - (4C + 4B) = 42 - 40
B = 2
So a beef pastry costs $2. Answer: \boxed{2}.