# The Taxi Problem
C.1.Aims2
Aim 6: The energy density of different fuels could be investigated experimentally.
The year is 2000. You have been appointed the 🚚 Transport Secretary of Hong Kong 🇭🇰. It is known to be "more environmentally friendly" for cars to run on LPG instead of gasoline, and you want the taxis 🚕 to all change to using LPG. Fuel costs are actually lower using LPG too, so it's win-win all around.
However, using LPG requires switching out the engine (which is expensive) and the taxi owners are asking for a subsidy. The Chief Executive asked you to make a decision about how much 💰 is the right subsidy.