# Thread: Probability Question (Percentage)

1. ## Probability Question (Percentage)

Delete this post! I double posted!

2. ## Re: Probability Question (Percentage)

Originally Posted by iHaveDiarrheaProbs
I don't have a clue how to solve this question. "Din is the coach of a soccer team. Base on the team's record, it has a 70% chance of winning on calm days and a 50% chance of winning on bad days. Tomorrow there is a 30% chance of bad day. There are no ties in Din's soccer team record. What is the probability that Din's team will win tomorrow? Show me how you solve it."

Can someone pls just show me the step by step how to solve it?

\begin{align*} &P[\text{winning tommorow}] = \\ &P[\text{winning tomorrow | tomorrow is calm}]P[\text{tomorrow is calm}]+ P[\text{winning tomorrow | tomorrow is bad}]P[\text{tomorrow is bad}] = \\ &(0.7)(1-0.3) + (0.5)(0.3) = \\ &0.49 + 0.15 = 0.64 \end{align*}

3. ## Re: Probability Question (Percentage)

Originally Posted by iHaveDiarrheaProbs
I don't have a clue how to solve this question. "Din is the coach of a soccer team. Base on the team's record, it has a 70% chance of winning on calm days and a 50% chance of winning on bad days. Tomorrow there is a 30% chance of bad day. There are no ties in Din's soccer team record. What is the probability that Din's team will win tomorrow? Show me how you solve it."
Tomorrow has a 70% chance of being F(fair weather. WHY?
If $B~\&~W$ stand for "bad weather" and "winning" resp.

$\mathcal{P}(W)=\mathcal{P}(W\cap F)+\mathcal{P}(W\cap B)=\mathcal{P}(W|F)\mathcal{P}(F)+\mathcal{P}(W|B) \mathcal{P}(B)$

$\mathcal{P}(W|B)\mathcal{P}(B)=(0.5)(0.3)$ WHY?

$\mathcal{P}(W|B)$ stands for "probability of winning given bad weather".