Question

A cup of coffee cools from 90°C to 80°C in t minutes, when the room temperature is 20°C. The time taken by a similar cup of coffee to cool from 80°C to 60°C at a room  temperature same at 20°C is ______.

विकल्प

• `10/13`t

• `5/13`t

• `13/10`t

• `13/5`t

Answer 1

A cup of coffee cools from 90°C to 80°C in t minutes, when the room temperature is 20°C. The time taken by a similar cup of coffee to cool from 80°C to 60°C at a room  temperature same at 20°C is `13/5`t.