Answer:
1:50 PM
Explanation:
Left school at 10:38 AM,
took them 51 minutes,
38+51=89,
89-60=29,
so when they drove to the museum, it was 11:29 AM.
From here, they stayed at the museum for 1 hour and 26 minutes,
so they stayed at the museum until 12:55 AM since 29+26=55.
Now, it took them 55 minutes to drive back to the school,
so 12:55 plus another 55 minutes,
it's going to be 1:50 PM when Dale's class got back to school.