Final answer:
To find the probability of Lena winning a prize, divide the favorable outcomes by the total outcomes using the odds in favor. The probability of Lena winning a prize is 5/12.
Step-by-step explanation:
To find the probability of Lena winning a prize, we can use the odds in favor of her winning. The odds in favor are given as 5/7. The probability can be found by dividing the favorable outcome (Lena winning) by the total number of possible outcomes.
So the probability of Lena winning a prize is:
P(Lena winning) = favorable outcomes / total outcomes
P(Lena winning) = 5 / (5+7)
P(Lena winning) = 5/12