Answer:
So you are given a choice of black or tan pants, and in shirts yellow, red, green or white. Therefore the possible combinations for red are: 
Black pant + red shirt 
Tan pant + red shirt 
Possible combinations for yellow are: 
Black pant + yellow shirt 
Tan pant + yellow shirt 
Possible combinations for green are: 
Black pant + green shirt 
Tan pant + green shirt 
Possible combinations for white are: 
Black pant + white shirt 
Tan pant + white shirt 
Therefore you have a total of 8 different assortments of pants and shirts.