The price of wheat has increased by `25 %.` Find the reduction in consumption so that there is no change in the expenditure.

Answer

To solve the problem of finding the reduction in consumption of wheat due to a 25% increase in its price while keeping the expenditure constant, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Initial Situation**:
- Let the initial price of wheat be `100` (this is a hypothetical value for simplicity).
- Let the initial quantity of wheat consumed be `1 unit`.
- Therefore, the initial expenditure is:
\[ \text{Expenditure} = \text{Price} \times \text{Quantity} = 100 \times 1 = 100 \]

**Hint**: Start by defining the initial price and quantity to establish a baseline for calculations.

2. **Calculate the New Price After Increase**:
- The price of wheat has increased by `25%`.
- The new price can be calculated as:
\[ \text{New Price} = \text{Old Price} + \left(\frac{25}{100} \times \text{Old Price}\right) = 100 + 25 = 125 \]

**Hint**: To find the new price after a percentage increase, add the percentage of the old price to the old price.

3. **Determine the New Quantity that Can Be Bought with the Same Expenditure**:
- We want to find out how much quantity can be bought with the same expenditure of `100` at the new price of `125`.
- The new quantity can be calculated as:
\[ \text{New Quantity} = \frac{\text{Expenditure}}{\text{New Price}} = \frac{100}{125} = \frac{4}{5} \text{ units} \]

**Hint**: To find the new quantity, divide the total expenditure by the new price.

4. **Calculate the Reduction in Consumption**:
- The reduction in consumption can be calculated as:
\[ \text{Reduction} = \text{Initial Quantity} - \text{New Quantity} = 1 - \frac{4}{5} = \frac{1}{5} \text{ units} \]

**Hint**: The reduction in consumption is simply the difference between the initial quantity and the new quantity.

5. **Calculate the Percentage Reduction in Consumption**:
- To find the percentage reduction in consumption, use the formula:
\[ \text{Percentage Reduction} = \left(\frac{\text{Reduction}}{\text{Initial Quantity}}\right) \times 100 = \left(\frac{\frac{1}{5}}{1}\right) \times 100 = 20\% \]

**Hint**: To express the reduction as a percentage, divide the reduction by the initial quantity and multiply by 100.

### Final Answer:
The reduction in consumption should be `20%` to maintain the same expenditure after the price increase.