20 kg of a mixture of wheat and husk contains 5% husk. How many kg more of husk must be added to make the husk content 20% in the new mixture?

Step 1: Understand the initial setup

• Total mixture = 20 kg
• Husk = 5% of 20 kg = (5/100) × 20 = 1 kg
• Wheat = 20 - 1 = 19 kg

Step 2: Let x kg of husk be added

• New total husk = 1 + x
• New total mixture = 20 + x
• We want husk to be 20% of the new mixture:

(1 + x) / (20 + x) = 20 / 100
⇒ (1 + x) / (20 + x) = 1 / 5

Step 3: Cross-multiply and solve

5(1 + x) = 20 + x
5 + 5x = 20 + x
5x - x = 20 - 5
4x = 15
x = 15 / 4 = 3.75

Answer: 3.75 kg

To make the husk content 20%, you must add 3.75 kg of husk to the original 20 kg mixture.