A body cools from `50^(@)C` to `46^(@)C` in 5 minutes and to `40^(@)C` in the next 10 minutes. The surrounding temperature is :

Options

A. `30^(@)C`
B. `28^(@)C`
C. `36^(@)C`
D. `32^(@)C`

Answer

A

Explanation

`(d theta)/(dt)=K(theta_(av)-theta_(0))`
`(4)/(5)=K(48-theta_(0))` . .. (i)
`(6)/(10)=K(43-theta_(0))` . .. (ii)
`(4)/(5)xx(10)/(6)=((48-theta_(0)))/((43-theta_(0)))`
`(4)/(3)=((48-theta_(0)))/((43-theta_(0)))`
After solving,
`theta_(0)=30^(@)C`.