Solution:

Brian is the one who speaks truth.

Adam is lying about Brian. Also Cody Is lying since Brian does not lie. Thus Brian is the one speaking truth. Any other combination will fail to come out true.

Solution:

No Excuse

Explanation:
Since there is no X listed =>No Excuse

Solution:

Impossible

Explanation:
Let us first denote everything with variables.
d= distance to your friend's place
T = time taken to get there
t = time required to get back
R = Speed while returning back

d = 20T
T = d/20

d = Rt
t = d/R

We have made equations for T and t and now we can derive an equation for the round trip.

2d = 40(T + t)
2d = 40(d/20 + d/R)
2d = 40d(1/20 + 1/R)
1 = 20(R/20R + 20/20R)
20R = 20(R+20)
R = R + 20

Do you see the paradox here? You literally have to travel back at an infinite speed if you want to make the average speed of your trip 40 mph. The faster return speed will have lesser impact of the average speed but consider that the quicker your return trip is, the faster you will make it.

We are talking about travelling double the distance in the same time that was taken for one way trip. Thus, if you travel at infinite speed, you will be able to attain an average of 40 mph.

Solution:

Yes, a Palm Tree.

Bonzai can be logical solution

Solution:

For(4) + a + change(delta/change symbol)
= For a change

Solution:

Route(Root symbol) + 66
= Route66

Solution:

Falling In Love

Solution:

Ruskin Stole Chihuahua
Sam stole Hyena
Terry Stole Deer

Explanation:
Let us consider the first two statements again; they are conflicting. However both can be true together. Also both of them cannot be incorrect which means that Terry stole Chihuahua and his statement will be true. But it has been already inferred that the one who stole Chihuahua was telling a lie thus it can’t be possible.

Focus on the given facts again. Terry might have stolen a hyena or a deer. Let us say that he stole hyena. In such an event the statement of Terry will be untruthful. But we know that the person who stole hyena told the truth, thus it is controverting our hypothesis and so cannot be true.

Considering everything, now we can be sure of the fact that Terry stole the deer.

It means that the declaration by Ruskin is totally false and the declaration by Sam is true which shows that the Chihuahua and hyena are stolen by these two. Also we know that the one who stole hyena is correct and the one stealing Chihuahua is a falsifier. Thus we now know that Ruskin stole Chihuahua and Sam stole hyena.

Solution:

None.

Yolk of the egg is yellow.

Solution:

Misunderstood