c) Suppose there are 10 people ({A, B,C, D, E, F,G, H, I, J}) who need to be photographed for a portrait. How many ways are there to take a picture of these ten people such that A, B,C are always next...

Extracted text: c) Suppose there are 10 people ({A, B,C, D, E, F,G, H, I, J}) who need to be photographed for a portrait. How many ways are there to take a picture of these ten people such that A, B,C are always next to each other. They do not have to be in the order ABC d) How many non-negative integer solutions are there to the following problem? I1 + x2 + x3 = 10 where x > 2