A red food coloring recipe says, "Mix `4` tbsp raspberry juice with `3` tbsp strawberry juice and `2` tbsp water."
Kiran wants to make `45` tbsp of red food coloring. He has plenty of water, but he only has `24` tbsp of raspberry juice and `21` tbsp of strawberry juice.
What is the most food coloring Kiran can make using the ingredients he has?