Help and explanation with this probability question would be really appreciated :)

Answer:
b
Step-by-step explanation:
The probability (PB) is .4 or 4/10 or 2/5.
So, we'd do a proportion.
2/5=x/6
Cross multiply.
5x=12
Divide by sides by 5.
x=2.4
We round up to account for the .4
so b
I can't answer c right now, but I'll come back once my class is over :)