Answer:
48h
Explanation:
Manny's amount of pictures will be represented by 36h, since he takes 36 every hour.
Colby's amount will be represented by 12h, since he takes 12 per hour.
Add these two together to get an expression:
36h + 12h
= 48h
So, 48h is the expression that can describe the combination of both of their pictures.