This is a bit of a guess, but I think probably a) +4 and also a) -215
Probability that both roads from a to b are blocked is the product of the individual probabilities, i.e.
P(~ab)=0.25*0.25=0.0625
Similarly
P(~bc)=0.25*0.25=0.0625
Probability that EITHER one or both of ab and bc are blocked is the sum of the probabilities:
P(~ab ∪ ~bc)=0.0625+0.0625=0.125
(recall that one cannot travel from a to c if either ab or bc is blocked.)
Therefore the probability that there exists an open route from a to c
= P(ac) = 1-P(~ab ∪ ~bc)
= 1 - 0.125
=0.875
Answer:

Step-by-step explanation:
To avoid confusion, distribute the negative amongst all terms in the second set of parentheses.
I hope this helps you out alot, and as always, I am joyous to assist anyone at any time.
Answer:
Step-by-step explanation:
(5f-3)(-2)
-10f + 6 = 0
f= 6 + 10
f = 16
Answer:
3/4 of cookie per each friend.
Step-by-step explanation:
Since you have 4 friends, and only have 3 cookies,
the fraction is 3/4. why? because 3/4= 0.75
which makes 0.75x 4 friends= 3 cookies . Each friend will get 0.75 or 75% of cookie which is the same as 3/4.