Expenditure of company B in 2009 and 2010 are Rs. 12 lakhs and Rs. 14.5 lakhs respectively. What was the total income of company B in 2009 and 2010 together (in lakh rupees)?

Answer: Option B

Profit percent earned by company B in 2009 = 35%
Profit percent earned by company B in 2010 = 50%
Expenditure of company B in 2009 = 12 lakhs
Expenditure of company B in 2010 = 14.5 lakhs
Income of company B in 2009
$$\begin{array}{rl}& 35\%=\frac{I-E}{E}\times 100\\ & \Rightarrow 35=\frac{I-12\text{ lakh}}{12\text{ lakh}}\times 100\\ & \Rightarrow \left(35\times 12\right)\text{lakh}=100I-1200\text{ lakh}\\ & \Rightarrow 420\text{ lakh}=100I-1200\text{ lakh}\\ & \Rightarrow I=16.20\text{ lakh}\\ & \text{Income of company B in 2009}\\ & 50\%=\frac{I-E}{E}\times 100\\ & \Rightarrow 50=\frac{I-14.5\text{ lakh}}{14.5\text{ lakh}}\times 100\\ & \Rightarrow \left(50\times 14.5\right)\text{lakh}=100I-14.50\text{ lakh}\\ & \Rightarrow 2175\text{ lakh}=100I\text{ lakh}\\ & \Rightarrow I=21.75\text{ lakh}\end{array}$$
So,
Total income of company B in 2009 and 2010
= 16.2 + 21.75
= Rs. 37.95 lakhs