Please show me how to calculate this problem: The school cafeteria sells two kinds of wraps: vegetarian and chicken. The vegetarian wrap costs $1.00 and the chicken wrap costs $3.20. Today they made $99.20 from the 42 wraps sold. How many of the wraps sold were vegetarian?

Answer 1

total sales:
total wraps:

1.00v + 3.20c = 99.20
v + c = 42

subtract one equation from the other:

2.20c = 57.20
c = 26
so, v = 16