Q.Four married couples have gathered in a room.Two persons are selected at random amongst them,find the probability that selected persons are a gentleman and a lady but not a couple.
<a>1/7 <b>3/7 <c>1/8 <d>3/8
Please alo show the detailed steps to the final ans.................
There are total 8 people in the room. from them 2 people can be selcted in 8C2 ways i.e. 28 ways. Now to select a gentleman we can do it in 4 ways( 4 men). now to select a lady we can select her in 3 ways (as we cannot select the spouse of the gentleman). so total no. of ways to in which a gentleman and lady can be selected such that they are not married is 4*3=12 ways. so probability is 12/28 = 3/7 answer is (b)
4 married couple = 8 (1+1
1+1
1+1
1+1)
two persons selected at random= 8c4
selected person are gentleman & lady but not a couple are = 8c0 * 8c0
therefore, 8c0*8c0/8c4 = 1*1/8*7*6*5/4*3*2*1 = 1/70 answer
The ans is 3/7.......not 1/70!!!!
CAclubindia
