i think it depends on if you have enough money to buy the books you need so C would be the answer
Answer:
0.78
Step-by-step explanation:
We have the next probability distribution:
X P(X)
0 0.2
1 0.3
2 0.5
As we can see when we add all the probabilites the result is 1. Now calculating the mean we have:

The standard deviation is:

Then using the data that we have:

Then the standard deviation is 0.78
Watch videos on YouTube, that's what I do with geometry.
Answer:
16 girls
Step-by-step explanation:
boys : girls : total
5 4 5+4 = 9
take the total number of people and divide by 9
36/9 = 4
Each number should be multiplied by 4
boys : girls : total
5*4 4*4 9*4
20 16 36
There are 16 girls