In a shell$-$and$-$tube heat exchanger, hot water is pumped through the pipe at a rate of $3,000[$kg$/$hr$]$ and cooled from $55[]$ to $40[].$ Meanwhile, on the outside, coolant flows at a speed of $5,000[$kg$/$hr$]$ at $25[].$ Find the amount of heat transfer through the heat exchanger.

Put $1,800[$kg$]$ of $110[]$ oil $($specific heat $0\mathrm{.}45$ kcal$/$kg$)$ into the inner tube of a double pipe heat exchanger and take it out when the temperature is $45[].$ Add water $($countercurrent$)$ to the pipe wall at $20[]$ and take it out at $50[].$ If the inner diameter of the pipe is $36[$mm$]$ and the overall heat transfer coefficient based on the inner area is $500[$kcal$/$m$^2$hr$],$ what is the required heat transfer area $[$m$^2]?$