Kwame = 2.5 hours * 60 minutes = <<2.5*60=150>>150 minutes
Connor = 1.5 hours * 60 minutes = <<1.5*60=90>>90 minutes
Kwame + Connor = 150 + 90 = 240 minutes
240 - 97 = <<240-97=143>>143 minutes
Kwame and Conner studied 143 minutes more than Lexia.
#### 143