Random Puzzles 

Workings

Hint
Cockroaches have 6 feet, mice have 4, and birds have 2. They each have one head.

Answer
35 birds, 5 mice, and 10 cockroaches.

Reasoning
Cockroaches have 6 feet, mice have 4, and birds have 2. They each have one head.

We can write down expressions for the heads and the feet – calling birds B, mice M, and cockroaches C.

Counting the heads:
(1)    B +  M +  C =  50

Counting the feet:
(2)   2B + 4M + 6C = 150

We are told that for every mouse there are two cockroaches so, C = 2M. Update (1) and (2) to give:
(3)    B +  3M =  50
(4)   2B + 16M = 150

If we double (3) we get:
(5)   2B +  6M = 100

We can now do (4) – (5) to give:
 10M = 50
   M = 5

So, we have 5 mice (and 10 cockroaches).

We can use M = 5 in (3) to give:
 B + 3 x 5 = 50
    B + 15 = 50
         B = 35

So, C = 10, M = 5 and B = 35.

Double-Checking
10 cockroaches have 10 heads and 60 feet.
5 mice have 5 heads and 20 feet.
35 birds have 35 heads and 70 feet.

The total number of heads = 10 + 5 + 35 = 50.

The total number of feet = 60 + 20 + 70 = 150.

Workings

Hint
Start by filling the 11 gallon container.

Answer
Here are the contents of the containers after each stage:
A  B
0  11  fill B
7  4   fill A from B
0  4   empty A
4  0   fill A from B
4  11  fill B
7  8   fill A from B
0  8   empty A
7  1   fill A from B
0  1   empty A
1  0   fill A from B
1  11  fill B
7  5   fill A from B
0  5   empty A
5  0   fill A from B
5  11  fill B
7  9   fill A from B
0  9   empty A

This leaves 9 gallons in container B.

Workings

Hint
The word JULY appears 64 times.

Answer
The word JULY appears 64 times.

Workings

Hint
Start on any square, and see how far you get.

Answer
Start from the 2R on the sixth row down and the second column across.