To find the smaller side of a rectangular prism on each end you must multiply the width and height:
15*8=120
Then you must times this by 2 because we have 2 of those sides (one on each end):
120*2=240
Then find the rectangular shape's surface area by multiplying the length and the height:
10*8=80
You must then multiply this by 4 as there are four of those sides:
80*4=320
Then add the two answers together to find the total surface area:
320+240=560