A body cools in $7$ minutes from $60^{\circ}\,C$ to $40^{\circ}\,C$. The temperature of the surrounding is $10^{\circ}\,C$. The temperature of the body after the next $7$ minutes will be
$\frac{40-T}{7}=K\left(\frac{40+T}{2}-10\right) \ldots$ (ii)
From $(i)$ and $(ii)$
$T =28^{\circ}\,C$
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