Question

Fiona has to choose a bouquet for her wedding. The probability that she uses red roses is 98%, the probability that she uses orchids is 87%, and the probability that she uses Gerber daisies is 94%. Given the probability that she has both roses and orchids is 0.87 and the probability that she has both Gerber daisies and roses is 0.97 what is the probability that her bouquet contains roses or Orchids?

Answer 1

92.5% i think or its 93%

Answer 2

98% chances

Explanation:

In this problem, we have to use the probability of union, because the question is asking for one event or the other to happen, it's not the probability of one "and" the other, because in that case would be intersection probability.

Always when we have the conditional "or", it means union. This probability is define as:

`P(A \ or \ B)=P(A) + P(B) - P(A \ and \ B)`

So, A would be roses and B would be orchids.

The probability of roses is 98%, the probability of orchids is 87% and the probability of both (intersection) is 0.87.

Replacing in the formula, we have

`P(A \ or \ B)=0.98 + 0.87 - 0.87=0.98`

Therefore, there's a 98% chances to contain roses or orchids.