Answer:
Step-by-step explanation:
Hi Millie.
First we can realize that the number of cubes of each type does not matter, only the ratios between them. We see that if there are x yellow cubes, there are 3x blue cubes. And therefore, there are 5*3x green cubes, or 15x green cubes. This means that the cubes are in a 1:3:15 ratio, or that for every 1 yellow cube, there are 3 blue and 15 green cubes.
Now we can find the probability of picking a yellow cube. Since there are 18 non-yellow cubes for every yellow cube, this means that there is a 1/19 possibility of picking a yellow cube.
Step 1: x²-15=2x
step 2: x²-2x-15=0
step 3: (x-5)(x+3)=0
step 4: x-5=0 or x+3=0
step 5: x=5 of x=-3
The probability any one system works is 0.99
So the probability of any one system failing is 1-0.99 = 0.01, so basically a 1% chance of failure for any one system
Multiply out the value 0.01 with itself four times
0.01*0.01*0.01*0.01 = 0.000 000 01
I'm using spaces to make the number more readable
So the probability of all four systems failing is 0.00000001
Subtract this value from 1 to get
1 - 0.00000001 = 0.99999999
The answer is 0.99999999 which is what we'd expect. The probability of at least one of the systems working is very very close to 1 (aka 100%)
2 bc you can’t write it as a fraction
