Bob drove for one and a half hours at 60/mph.  He then hit construction and drove for 2 hours at 45/mph. How many miles did Bob travel in those 3 and a half hours?
How many miles did Bob drive in the first 1.5 hours? ** Bob drove for 1.5 hour * 60/mph = <<1.5*60=90>>90 miles.
How many miles did Bob drive in the second 2 hours? ** Bod drove for 2 hour * 45/mph = <<2*45=90>>90 miles.
How many miles did Bob drive in those 3 and a half hours? ** In total Bob drove 90 + 90 miles = <<90+90=180>>180 miles.
#### 180