I'm thinking $10 more or less. It depends on whether you get stuck on Lake Shore Drive in the construction. However, Chicago is running their free trolleys. I know they go to the Museum Campus (which includes the aquarium and the Field Museum). You might want to check with the Hotel to see if the trolleys run to the Science & Industry (which is a bit further south).
And Diva is absolutely right about our cab drivers. Chicago cabs can go from zero to 90 in less than 10 seconds.
Try to get to the Field Museum too. There is a baseball exhibit opening. There is some Egyptian art on display too. Oh, and the "Wild Reef" just opened at the aquarium.
Cyn