A chair costs x naira, and a table costs a naira more than a chair. Find the difference in cost between four chairs and one table.

The cost of one table is x + a naira.

The cost of four chairs is 4x naira.
The difference in cost between four chairs and one table is:

4x - (x + a) = 3x - a naira.

Let's break down the problem step by step:

1. Let's start by assigning variables to represent the cost of the chair and table:
- Cost of the chair: x naira
- Cost of the table: x + a naira (where a represents the additional cost of the table)

2. We know that the table costs a naira more than the chair, so we can write an equation:
x + a = cost of the table

3. We need to find the difference in cost between four chairs and one table:
- Cost of four chairs: 4 * x naira
- Cost of one table: x + a naira

4. To find the difference, we subtract the cost of one table from the cost of four chairs:
Difference in cost = (4 * x) - (x + a)

Therefore, the difference in cost between four chairs and one table is (4 * x) - (x + a) naira.