Answer:
4/9 probability
Explanation:
Imagine winning something, there's 3 possible prizes that you get to choose from and get to keep let's say 4 days? These all written on the paper that you must pull from a box.
Your three prizes are
D1 D2 D3 D4
1. a car
2. a bike
3. skateboard.
Now if you can imagine a grid and you mark 1 dot in each day we'll end up with 12 slots total.
Let's say you don't want a skateboard you rather have a car or a bike. We need to figure out of the 12 possibility (assuming all are equal) What's the possibility of you pulling out anything BUT a skateboard?
You want at least 3 days in either or. So we must find P = (Days without skateboard)
We know it's all equal outcomes, you're going to get 1 day of that 1 item.. soo..
p (DWS) = _____
12 outcomes
Now you want how many days MORE THAN 3, can you use anything but the skateboard?
You have 3 & 4 days with a car...
You have 3 or 4 days with a bike.. Which gives us 4 of the days we do want!
Giving your final problem the looking like this .. P(DWS) = 4/9
In respects/C to KhanAcademy.