EXPLANATION
Let's consider the facts:
The surface of a rectangular prism is given by the following equation:
Area= bh * L( S1 + S2 + S3)
Now, considering the sides:
Base = b = 8inches
Height = h = 6 inches
Length = L = 15 inches
Slope = 10 inches
Computing b*h = 8 inches * 6 inches = 48 in^2
Now, we need to find S1, S2 and S3
S1 = Base = 8 inches
S2 = Slope = 10 inches
S3 = Slope= 10 inches
So the Area is:
Area= 48 + 15*(8 + 6 + 10)
Adding terms:
Area = 48 + 15*(24)
Multiplying terms:
Area = 48 + 360
Adding terms:
Area = 408 in^2
The answer is 408 in^2