A)2 B)799 C)159600 D)63520800
This looks difficult...but it's not.....
Notice that 400! / 398! = (400 x 399 x 398 x 397.......) / (398 x 397 x 396 x 395...)
All all the terms on the "top" cancel with all the terms on the "bottom" except 400 x 399
Can you take it from here??
The answer is 159600 right? thanks for the help!!!
Yep....that's it !!!