Shell & Tube heat exchanger $($Trim cooler$)$ question.

Stream $1=90$ deg c

Stream $2=75$

Stream $3=25$

Stream $4=35$

Tube side $=$ Stream $1$&$2($Hot lean solvent$)$

Shell side $=$ Stream $3$&$4($Cooling water$)$

Calculate $R$ value, $S$ value and LMTD