Brain Teasers and Puzzles 

Workings

Hint
There are three animals.

Answer
There are currently 6 different answers, can you find another?

Zebra, guitar, quick, way, box, vowel, monkey, eel, raj, package, sill, moon, heap, deep, fun.

Zebra, guitar, quick, say, box, vowed, monkey, eel, raj, package, hill, moon, leap, weep, fun.

Zebra, guitar, quick, sad, box, vowel, monkey, eel, ray, package, will, moon, heap, jeep, fun.

Zebra, guitar, quick, jam, box, vowel, donkey, eel, ray, package, will, moon, heap, seep, fun.

Zebra, guitar, quick, jaw, box, vowel, monkey, eel, ray, package, fill, moon, heap, deep, sun.

Zebra, guitar, quick, lay, box, vowed, monkey, eel, ran, package, will, mojo, heap, seep, fun.

Workings

Hint
Think of Roman numerals.

Answer
FO10.

Where Roman numerals exist they are replaced by their modern equivalents.

CLICK = 100 50 1 100 K
I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000

Workings

Hint
The first digit in each row is even, so the first column can only be 2 + 8, 4 + 6, 4 + 8, 6 + 8 (either way around, and it must be a total over 9).

Answer
423 + 675 = 1098.

Reasoning
Remembering that:
   even + even = even
   odd  + odd  = even
   even + odd  = odd

To discuss individual letters, it's easiest to represent the sum as:
   A B C
   D E F +
————————
 G H I J

A and D are both even, and can only be 2 + 8, 4 + 6, 4 + 8, 6 + 8 (either way around, and it must be a total over 9), so the carry can only be 1, so G = 1.

Since column 2 is even + odd = odd, there can be no carry from column 1 (since even + odd + 1 is always even). Therefore, neither C nor F (both odd) can be 7 or 9 (otherwise there would be a carry), so C and F are 3 and 5 (but we don't yet know which is which), therefore J = 8.

Because A + D is even there can't be a carry from column 2, therefore E can't be 9 as this would force a carry. Therefore, I = 9. So, B can't be 0. Therefore, H = 0.

The last remaining odd number makes E = 7. Making B = 2.

Therefore, A and D are 4 and 6 (but we don't yet know which is which).

Since the top row's digits have to add to 9 the top number must be 423.

This makes the sum 423 + 675 = 1098.

Workings

Hint
What would happen in 36 hours?

Answer
7 hours and 12 minutes.

Firstly we find a time that both 12 hours and 18 hours would fit in to...

In 36 hours:

   6 large pipes can drain 3 reservoirs.
   6 small pipes can drain 2 reservoirs.

Therefore, together, 6 large and 6 small pipes can drain 5 reservoirs.

36 hours ÷ 5 = 7.2 hours.

7.2 hours = 7 hours and 12 minutes.