Puzzle 1
Using a 3 gallon container and a 7 gallon container (along with a water source and drain) …
… can you measure exactly 5 gallons in the fewest steps?
Puzzle Copyright © Kevin Stone
workings
hint
answer
print
www.brainbashers.com
/puzzle/zzmq
share
Hint
Start by filling the 7 gallon container.
Answer
Here are the contents of the containers after each stage:
A B
0 7 fill B
3 4 fill A from B
0 4 empty A
3 1 fill A from B
0 1 empty A
1 0 fill A from B
1 7 fill B
3 5 fill A from B
This leaves 5 gallons in container B after 8 steps.
Puzzle 2
Using the letters AAAAEERRRRTT complete this grid. The grid reads the same across as down.
Note: this puzzle is not interactive, and the squares cannot be clicked.
Puzzle Copyright © Kevin Stone
workings
hint
answer
print
www.brainbashers.com
/puzzle/zrpg
share
Hint
One of the words is AREA.
Answer
S
T
A
R
T
A
R
E
A
R
E
A
R
E
A
P
Puzzle 3
My local greengrocer is a would-be mathematician.
She likes to arrange the apples in nice rows.
When she lays the apples in rows of 3, she has one left over.
And, when she lays them in rows of 5, she also has one left over.
Remarkably, she also has one left over when she arranges them in rows of 7 and 9.
But 11 seems to be the magic number, because in rows of 11 there are no apples left over.
How many apples does she have?
Puzzle Copyright © Kevin Stone
workings
hint
answer
print
www.brainbashers.com
/puzzle/zocw
share
Hint
There are fewer than 1,000 apples.
Answer
946 apples.
Reasoning
We know that (answer − 1) is divisible by 3, 5, 7, and 9.
If it's divisible by 9 then it's automatically divisible by 3.
So the number must be a multiple of 5, 7, and 9.
[5 x 7 x 9 = 315]
Since these numbers share no other common factors, we know that the answer must be a multiple of 315 (+ 1).
Let's try 1 x 315 + 1: 316 ÷ 11 = 28.73, and this doesn't work.
Let's try 2 x 315 + 1: 631 ÷ 11 = 57.36, and this doesn't work.
Let's try 3 x 315 + 1: 946 ÷ 11 = 86, and this works, and is the answer.
Puzzle 4
Starting with SOFT, change one letter at a time until you have the word LENS.
Each change leaves the other letters in their original places and must result in a proper word.
What is the minimum number of steps required to achieve this change?
SOFT
....
....
....
LENS
Puzzle Copyright © Kevin Stone
workings
hint
answer
print
www.brainbashers.com
/puzzle/zvtf
share
Hint
The first change makes SOFT into LOFT.
Answer
SOFT, LOFT, LEFT, LENT, LENS.
next >