A body cools from \(80\) °C to \(50\) °C in \(5\) minutes. The time it takes to cool from \(60\) °C to \(30\) °C is:
(The temperature of the surroundings is \(20\) °C)
1. \(13\) min
2. \(15\) min
3. \(12\) min
4. \(10\) min