The surface area of 10cm, 15cm, and 10cm is found by splitting the dimensions to many different equations.
1st equation: 10 times 15
2nd equation: 10 times 10
3rd equation: 10 times 10
4th equation: 10 times 15
5th equations: 10 times 15
6th equation: 10 times 15
You would then add all the solutions up to get the final solution.
The answer is...
800