DSE PROBABILITY QUESTIONS

[tania]

Q1. Two women and 4 men are to be seated randomly around the circular table . Find the probability that the women are not seated next to each other ?
1. 1/2
2. 1/3
3. 2/5
4. 3/5

Q2. A fair coin is tossed until a head comes up for the first time. The probability of this happening on an odd numbered toss is
1. 1/2
2. 1/3
3. 2/3
4.3/4

Please explain the answer.
Thanks.

[sasdthds]

q.1-3/5
q-2.1/2

[tania]

hey please post the solution.
thanks

[sasdthds]

for the first ques take the negative approach,
club the two women together as one and then 4 men
total person=5
no. of arrg then =4!2!
without cases=5!
ans=1-4!2!/5!
q.2 is based on binomial coeffient propeties