To buy 20 kg of items with a budget of 20 rupees, we need to consider the prices per kilogram of each item:

• Chicken: 20 rupees per kg
• Potato: 1 rupee per kg
• Onion: 0.25 rupees per kg

Let's break down how we can distribute the quantities within the 20-rupee budget while achieving a total of 20 kg:

Possible Combination:

1. Potato: $x$ kg

   • Cost: $x \times 1$ rupee per kg

2. Onion: $y$ kg

   • Cost: $y \times 0.25$ rupees per kg

3. Chicken: $z$ kg

   • Cost: $z \times 20$ rupees per kg

Given constraints:

• $x + y + z = 20$ kg (total weight)
• $x \times 1 + y \times 0.25 + z \times 20 = 20$ rupees (total cost)

Solving the Equations:

Let's try $z = 1$ kg of chicken, so:

• Cost of chicken = $1 \times 20 = 20$ rupees
• Remaining budget = $20 - 20 = 0$ rupees
• Remaining weight = $20 - 1 = 19$ kg

Given the budget is exhausted by the chicken, we cannot buy any potatoes or onions in this scenario.

Let's reduce the quantity of chicken and explore another possibility.

Another Option:

Suppose you don't buy chicken at all:

Let’s try only buying potatoes and onions:

• $x \times 1 + y \times 0.25 = 20$ rupees
• $x + y = 20$ kg

We can calculate $y$ in terms of $x$:

• $x + 0.25y = 20$
• $y = 20 - x$

Substitute in the cost equation:

• $x + 0.25(20 - x) = 20$
• $x + 5 - 0.25x = 20$
• $0.75x = 15$
• $x = 20$

This suggests:

• Potatoes: 20 kg
• Onions: 0 kg
• Total cost: $20 \times 1 = 20$ rupees

So, you can buy 20 kg of potatoes for exactly 20 rupees.

Conclusion:

• Buy 20 kg of potatoes to use exactly 20 rupees.

Would