Answer: on point -10
Step-by-step explanation:
Because 2*-5 is -10.
Answer:

And we can use the probability mass function and we got:
And replacing we got:

Step-by-step explanation:
Let X the random variable of interest "number of graduates who enroll in college", on this case we now that:
The probability mass function for the Binomial distribution is given as:
Where (nCx) means combinatory and it's given by this formula:
We want to find the following probability:

And we can use the complement rule and we got:

And we can use the probability mass function and we got:
And replacing we got:

Simplest form of:
12/30=2/5
12/20=3/5
21/35=3/5
Px + qy = r
2px - qy = 2r
----------------add
3px = 3r
x = 3r/3p
x = r/p