An arbitrary scale has the ice point at `-20^(@)` and the steam point at `180^(@)`. When the thermometer reads `5^(@)`, then find the read of centigrade thermometer.

Explanation

To solve the problem, we need to convert the reading of the arbitrary thermometer scale to the Celsius scale (centigrade). Here are the steps to find the Celsius equivalent when the arbitrary thermometer reads 5 degrees.

### Step-by-Step Solution:

1. **Identify the given points:**
- Ice point (0°C) corresponds to -20° on the arbitrary scale.
- Steam point (100°C) corresponds to 180° on the arbitrary scale.

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