Answer:
4
Explanation:
Since the value of the total prism is 28, and you know that there are two sides which are 2 from 2x1. Then you can subtract 4 from 28. You would have 4 sides left, 2 of which are px1 and the other 2 are 2xp. The total results would be 2p+4p which is 6p=24.