之前成都申友GMAT說到了GMAT數學排列組合的專業術語和解題方法，今天我們直接以例題的形式展現，看看大家是不是都掌握了方法。
1、There are 6 groups in a room.Each group consists of 3 men.How manyhandshakes will there be if each man only shakes hands with people who are outside his group。
解析：
18C2 - 6(3C2) = 18X17/2 - 6(3X2/2) = 153 - 18 = 135. I) 18 peopleshake had with each other or18C2 II) Then subtract the hand shakeswithin each group. Six such group with 6 hand shakes each or 6 (3C2)
2、if you tossed a coin three times, what' s the probability that you get the same side all three times.
解析：
the probability that you get one side 1/8 plus the probsbility that you get another side 1/8 totaling 1/4.
以上例題選自經典易錯難題，成都申友GMAT提醒一下準備研究GMAT數學排列組合的同學，一定要熟練的掌握公式，將公式中的每一項舉一反三的進行練習。