Reasoning There are 62 squares of size 1 x 1. There are 41 squares of size 2 x 2. There are 18 squares of size 3 x 3. There are 6 squares of size 4 x 4. There is 1 square of size 5 x 5.
Giving a total of 62 + 41 + 18 + 6 + 1 = 128 squares.
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Puzzle 199
Last week, I travelled from Birmingham to Glasgow, the long way round (on a bicycle!).
On day one, I travelled one quarter of the distance.
On day two, I travelled one half of the remaining distance.
On day three, I travelled three quarters of the remaining distance.
Yesterday I travelled one third of the remaining distance.
I now have 21 miles left to travel.
How far is it from Birmingham to Glasgow in total?
Hint
How many miles were left at the start of yesterday?
Answer
336 miles.
Reasoning
To work these numbers out, it is perhaps easier to start at the end and work backwards.
Yesterday I travelled 1/3 of the distance to leave 21 miles, therefore there were 31.5 miles (=21 ÷ 2/3) at the start of yesterday.
On day 3 I travelled 3/4 of the distance to leave 31.5 miles, therefore there were 126 miles (=31.5 ÷ 1/4) at the start of day 3.
On day 2 I travelled 1/2 of the distance to leave 126 miles, therefore there were 252 miles (=126 ÷ 1/2) at the start of day 2.
On day 1, I travelled 1/4 of the distance to leave 252 miles, therefore there were 336 miles (=252 ÷ 3/4) at the start of day 1.
Double-Checking
On day one, I travelled one quarter of the distance (84, leaving 252).
On day two, I travelled one half of the remaining distance (126, leaving 126).
On day three, I travelled three quarters of the remaining distance (94.5, leaving 31.5).
Yesterday I travelled one third of the remaining distance (10.5).
I now have 21 miles left to travel.
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Puzzle 200
Start in square 'S' and end in square 'E' moving either horizontally or vertically in each move. Start by moving 2 squares in each of your moves, but when you land on a '*' square, change the number of squares you move from 2 to 3, or vice versa. You can not step on or pass through the black squares and you have only 8 moves in which to complete this task.
