What The Surface Area Of Rectangular Prism 8m 5m 3m?

2((8 m)(5 m + 3 m) + (5 m)(3 m))
  = 2((8 m)(8 m) + 15 m^2)
  = 2(64 m^2 + 15 m^2)
  = 2(79 m^2)
  = 158 m^2