Random Puzzles 

Workings

Hint
The missing word is two letters long.

Answer
He.

To give:
..ir = heir
..ad = head
..lm = helm
..ed = heed
..lp = help

Workings

Hint
Do the words make any sense when read another way?

Answer
Ram.

These are the first three letters of the months in reverse order.

Therefore, RAM are the first three letters of March.

Workings

Hint
Try working backwards.

Answer
7,340 metres.

Reasoning
Stage 5's clue tells us that 150m was left. So the distance left at the start of Stage 4 must have been:
Dist4 = Dist4 + 75 + 150
        —————
          2

Which simplifies to give Dist4 = 450m.

Stage 3's clue tells us that 450m was one quarter of the remaining distance, so Dist3 = 1,800m.

Stage 2's clue tells us that the distance at the start of Stage 2 was:
Dist2 = Dist2 + 35 + 1800
        —————
          2

Which simplifies to give Dist2 = 3,670m.

Stage 1's clue tells us that 3,670m was half the overall distance, which means the entire ride was 7,340m.

Double-Checking
Starting with 7,340m:
Stage 1: cycled 3,670m, leaving 3,670m

Stage 2: cycled 1,870m, leaving 1,800m

Stage 3: cycled 1,350m, leaving   450m

Stage 4: cycled   300m, leaving   150m

Stage 5: cycled   150m, leaving     0m

Workings

Hints
The first 5 words begin with D, A, E, W, T.

Answers
--lta = delta --yss = abyss --pty = empty --dth = width --day = today --ybe = maybe --dex = index or codex --fth = fifth --nda = panda --aph = graph --alp = scalp --era = opera --njo = banjo --eue = queue --xty = sixty