Probability of Prevesh Paying Three Days in a Row: Coin Toss Lunch Break

[Amy-Lee]

Pravesh and Solly usually go to a coffee shop during their lunch break and toss a coin to see who will pay. The probability that Prevesh will pay three days in a row is

(1) 0.025
(2) 0.500
(3) 0.125
(4) 0.015

My attempt (I am not sure if this is right)

X= number of days that Prevesh will pay

x- P(x)
0 - 0.250
1 - 0.250
2 - 0.250
3 - 0.250

So I assume that the correct answer is (1)?

 

[Master7731]

i think since pravesh would have 1/2 chance of paying for a lunch on one day, you would have to multiply that by 3 and the odds become less for him to pay 3 times in a row therefore you would get 1/8 from 1/2 * 1/2 *1/2. Getting 0.125

 

[Amy-Lee]

Thank you

 

[berkeman]

i think since pravesh would have 1/2 chance of paying for a lunch on one day, you would have to multiply that by 3 and the odds become less for him to pay 3 times in a row therefore you would get 1/8 from 1/2 * 1/2 *1/2. Getting 0.125

Please do not do the OP's homework for him. It is cheating, and not allowed here at the PF.