Combination of Foursome Ten golfers are at the first tee waiting to start.(a) In how many ways can a foursome formed, not considering the wat in which the players are paired as partners? (b) After the first foursome has been formed, in how many ways can the second be formed? Answers: (a) $10C4$ = $210$ ways (b) $6C4$ = $15$ ways

Your answer to the first one is correct. Your answer to the second did incorrect though. After the first group has been formed, there are 6 people left to form a group out of, so the answer is $6C4$.