Answer:
600 g chicken
600 g peppers
120 g onion
15 g spice mix
6 tortillas
Explanation:
To make 18 portions, Carly needs to make 3 times the original recipe.
1. Solve for how much of each ingredient is needed.
500 · 3 = 1500 g chicken
600 · 3 = 1800 g peppers
90 · 3 = 270 g onion
25 · 3 = 75 g spice mix
12 · 3 = 36 tortillas
2. Subtract how much of each ingredient Carly already has from how much is needed to find how much more she needs.
1500 - 900 = 600 g chicken
1800 - 1200 = 600 g peppers
270 - 150 = 120 g onion
75 - 60 = 15 g spice mix
36 - 30 = 6 tortillas