You need to add 11.52 grams of pure onion powder to the blend to achieve a 20% concentration of onion powder in the final mixture.
Here's how to calculate how much pure onion powder should be added to the blend:
1. **Calculate the desired amount of onion powder in the final blend:**
- We want the final blend (72g) to have 20% onion powder.
- Therefore, the desired amount of onion powder in the blend is 20/100 * 72g = 14.4g.
2. **Calculate the amount of onion powder already present in the blend:**
- The existing blend is 4% onion powder by mass.
- So, the current amount of onion powder in the 72g blend is 4/100 * 72g = 2.88g.
3. **Calculate the amount of pure onion powder to add:**
- We need to add enough pure onion powder to reach the desired 14.4g of onion powder in the final blend.
- Therefore, we need to add 14.4g - 2.88g = 11.52g of pure onion powder.
**Therefore, you need to add 11.52 grams of pure onion powder to the blend to achieve a 20% concentration of onion powder in the final mixture.**