simple problem, simple solution
In the book, this is fully discussed!
In general, when you are faced with an increase in costs, here are the options
1. Increase selling price (your renter who is an engr will be earning P200 per month!!)
2. Increase volume of sales (cant do anything for apartment)
3. Increase efficiency (computerize etc

4. Get out of business (dont worry somebody else will replace you; did companies go out biz bec gasoline rose 3x from P20 to P60?)
Use the above formula for your problem below...
1. are there bakeries in Paris
2. are there fish vendors in Singapore
3. are there newspaper sellers in London?