Answer:
37 minutes
Explanation:
Carl spent 51 minutes less than Pete, so subtract.
3 hours = 180 minutes
180 - 51 = 129 minutes = 2 hours and 9 minutes
And Leah spent 1 hour 32 minutes less than Carl, so subtract again.
1 hour = 60 minutes + 32 = 92 minutes
129 - 92 = 37 minutes.