$($c$)$ Water flows at the rate of $85k\frac{g}{m}in$ through a double pipe counter flow heat exchanger. Water is heated from $50C$ to $95C$ by an oil flowing through the tube. The specific heat of the oil is $1\mathrm{.}680k\frac{J}{k}g.$ K$.$ The oil enters at $150C$ and leaves at $85C.$ The overall heat transfer co$-$efficient is $450\frac{W}{m^2}K.$ Calculate heat exchanger area and rate of heat transfer for counter flow.

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