You are considering insulating your bedroom to prevent heat loss. You are considering Type A and Type B insulation. Type A insulation can be installed for Rs. 160, and Type B for Rs. 240. You expect to save Rs. 35 per year in heating and cooling with Type A. If the interest rate is 6%, how much money approximately should you save per year in order to justify Type B insulation if you want to recover your investment in7 years? 

Pick the value closest to your answer 

a) Rs. 40 

b) Rs. 50 

c) Rs. 55 

d)Rs. 60