JNU SIS 2013 Question 3: Costs of production

A car manufacturing company wants to decide where to locate a new plant. The only inputs used in cars are steel and labour, and the production function is $f(S,\ L) = S^{\frac{1}{2}} L^{\frac{1}{2}}$, where $S$ is tons of steel and $L$ is units of labour. The company can locate its plant either in country $A$ or in country $B$. In country $A$, steel costs Rs 70 a ton and labour costs Rs 70 per unit. In country $B$, steel costs Rs 80 per ton and labour costs Rs 60 per unit. In which of the two countries should the company locate its new plant?