The answer is 8n^2
2x2 is 4 x 2 is 8 two n variables so multiple it by 2 and you get your answer
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%)
Alright, lets get started.
3 feet = 1 yard
If we cube both sides of the equation, we will get the conversion into cubic yards
So,

27 cubic feet = 1 cubic yards
So, 1 cubic feet =
cubic yards
So, 360 cubic feet =
cubic yards
So, 360 cubic feet = 13.33 cubic yards
13.33 cubic yards of air can it circulate per minute. : Answer
Hope it will help :)
If there is 5/6 left and he plans to eat 1/6 you do 5/6-1/6=4/6 of the pie
You do 9x27=243 then take 2x31=62 add 243+62=305 then take 305 and subtract it from 28 305-28=277
so if i did it right you should get n=277