In a double pipe cocurrent heat exchanger, operating at steady state, oil (specific heat capacity $=2100 \mathrm{~J} \mathrm{~kg}^{-1}{ }^{\circ} \mathrm{C}^{-1}$ ) entering at $7 \mathrm{~kg} \mathrm{~s}^{-1}$ at $100^{\circ} \mathrm{C}$ is used to heat water (specific heat capacity $=4200 \mathrm{~J} \mathrm{~kg}^{-1}{ }^{\circ} \mathrm{C}^{-1}$ ) flowing at $3.5 \mathrm{~kg} \mathrm{~s}^{-1}$ from $20^{\circ} \mathrm{C}$ to $50^{\circ} \mathrm{C}$. If the overall heat transfer coefficient is $291 \mathrm{~W} \mathrm{~m}^{-2}{ }^{\circ} \mathrm{C}^{-1}$, the required heat transfer area ( $\mathrm{in} ~\mathrm{m}^{2}$ ) is $\_\_\_\_$ (rounded off to one decimal place).
