(1) Clever Monkeys:  36 handshakes. You can arrive at this figure by following a permutation pattern. First monkey: 8 handshakes. Second monkey: 7 handshakes. Third: 6. Fourth: 5. Fifth: 4. Sixth: 3. Seventh: 2. Eighth: 1. Ninth: 0. Total = 36.

(2) Sandal Mania:  20,000 sandals.

(3) Bull's Eye:  2 shots on 16. 4 shots on 17.

(4) Calculated Training:   135 metres long.
1000 (metres in 1 kilometre) x 81 (km/hour) = 81000 metres/hour.
81000 divided by 60 = 1350 metres/minute.
1350 divided by 60 = 22.5 metres/second.

Next, 22.5 metres multiplied by the 6 seconds it took the train to pass by the passenger = 135 metres.

(5) Bearing Bonanza:   Image should be a dog with a tail facing west.

(6) Placing Problems:   Sarah, Dave, Anna, Sue, Dan.

(7) Fuzzy Farmer Logic:   The farmer had three animals.

(8) Dice rolling:  The order of rolls (number on top in brackets): 4 (2) --> 1(4) --> 2(1) --> 5(2) --> 4(4) --> 7(6)

(9) Look At It This Way:   1 = K, 2 = G, 3 = C, 4 = H

(10) Congruent Confusion:   Diagrams S and 4 are not congruent.

(11) Crayfish Can Be Square:

(12) Crazy Chess Guy:  Many solutions possible.