Not so good at math

A simple quiz for smart marketers:

Let's say your goal is to reduce gasoline consumption.

And let's say there are only two kinds of cars in the world. Half of them are Suburbans that get 10 miles to the gallon and half are Priuses that get 50.

If we assume that all the cars drive the same number of miles, which would be a better investment:

Get new tires for all the Suburbans and increase their mileage a bit to 13 miles per gallon.

Replace all the Priuses and rewire them to get 100 miles per gall