Calculate osmotic pressure of a solution obtained by mixing  100 ml of  3.4 % solution  
( wt / vol)  of urea$\left({\pi }_1\right)$ ( molecular weight 60 ) and 100 ml of  1.6 % solution ( wt / vol)  of cane sugar $\left({\pi }_2\right)$ at $20°C$(mol.Wt of cane sugar =342, R=0.0821 lit atm $mo{l}^{-1}{K}^{-1}$  )