For a mixture of acetic acid and toluene containing 0.486 mole fraction toluene, the partial pressures of acetic acid and toluene are found to be 0.118 bar and 0.174 bar respectively at 343 K. The vapour pressures of pure components at this temperature are 0.269 bar and 0.181 bar for toluene and acetic acid respectively. The Henrys law constant for acetic acid and toluene are 0.55 bar and 0.15 bar respectively. Calculate the activity and activity coefficient for toluene in the mixture (a) based on Lewis- Randall rule (b) based on Henrys law.