Random Puzzles 

Workings

Hints
The first letters of the words are: L, C, E, E, A, A, L, S, F, G, S, A, C, C, M.

Answers
---rnt = learnt ---few = curfew ---ryo = embryo ---yme = enzyme ---rak = anorak ---urd = absurd ---ynx = larynx ---mpi = scampi ---hom = fathom ---ovy = groovy ---lpt = sculpt ---hma = asthma ---voy = convoy ---web = cobweb ---mur = murmur

Workings

Hint
It doesn't matter what the distance is, so try a random distance.

Answer
This cannot be done.

It does not matter how far the trip is, let's assume that it is random distance, say 60 miles, and remembering that Time = Distance ÷ Speed.

The morning trip took 60 miles ÷ 30 mph = 2 hours.

To average the required 60 mph, we would have to travel the total distance (of 120 miles) in 2 hours. However, we've already used all of the two hours for the morning trip!

Choosing any random distance would also show that it can't be done.

Workings

Hint
The answer involves a square root.

Answer
4.

The middle of each triangle contains the square root of the sum of the three surrounding numbers.

Workings

Hint
The animal begins with the letter F.

Answer
Flamingo.
--ute = flute
c--el = camel
st--g = sting
car-- = cargo