Question

A person has a 30 percent chance of winning on a scratch-off lottery ticket. What is the probability she first wins of the fifth ticket
a. (5/1 ) (0.30)3 (0.70).
b. (5/4 ) (0.70)3 (0.30).
c. (0.70)^4 (0.30).
d. (0.30)^3 (0.70).
e. 0.30.

Answer 1

Answer: (c)

Step-by-step explanation:

Given

A person has a 30% chance of winning a lottery ticket.

Probability of not getting the lottery ticket is 70%

For person to win at fifth ticket, it must fail in first four

So, the probability associated with it is

$\Rightarrow P=(0.70)\times (0.70)\times (0.70)\times (0.70)\times (0.30)\\\\\Rightarrow P=(0.70)^4\cdot (0.3)$

Hence, option (c) is correct.