i have a little bit understanding problam....

1.basketball team have 10 players, how many posibilities the coach have to peek 5 players

so i did 10C5, and this is the correct answer in the book

but why 10*9*8*7*6 is not a good answer???

the coach have at the first peek 10 posibilities then 9 then 8.... so why this is wrong???

2. for a mission there is need to peek 2 officers of 5 and 3 soldiers of 8

how many posebilities exist?

so i did 5C2 * 8C3, but the answers in the book show that its a wrong answer. the good one is 5*4*8*7*6. im understand the process. that the first officer is 5 posibilities then 4 and soldiers is 8 posibilities the 7 then 6

but why the answer is in this whay and not 5C2 * 8C3 ??????