Question

The temperature of the body drops from 60°C to 40°C in 7 min. The surrounding temperature is 10°C. The temperature of the body drops from 40°C to T°C in 7 min. Find the value of T

• A. 16
• B. 20
• C. 28
• D. 30

Answer 1

Answer: (C)

28

Answer 2

The correct answer is option (C): 28

$\frac{60-40}{7}=K(50-10)$

$\frac{(40-T)}{7}=K(\frac{40+T}{2}-10)$

$\Rightarrow \frac{20}{40-T}=(\frac{40\times 2}{T+20})$

$\Rightarrow T+20=160-4T$

$\Rightarrow 5T=140$

$T=\frac{140}{5}=28^{\circ}$C