DAY 39

Comment

It might be easier to find the 100th pattern first.

Answer

Readers' methods

Adrian T, Loughborough LE11 5EH:
A careful inspection of the sequence reveals that odd multiples of 10 correspond to the diamond and even multiples of 10 to the diamond with a vertical line through it.
Thus, 100 = 10 x 10 which corresponds to a diamond with a vertical line through it.
And therefore 99 corresponds to the symbol one place to the left of that diamond, ie a square with a horizontal line through it.

Martin F, Manchester M21 9WH:
Since this is a repeating pattern of 4 items, to get the 99th divide 99 by 4 to give the remainder 3. The 99th symbol is then the same as the 3rd, namely the square with a horizontal line through it.

Lorna G, aged 16:
(Calling the symbols a, b, c, and d, as they appear in line)
it is a 4 symbol pattern, meaning that the numbers of the 4x table will dictate where symbol d occurs. The nearest number to 99 in the 4x table is 99/4 rounded down to the nearest whole number then x4, which is 24x4, which is 96. Therefore, the 96th symbol is symbol d, and as 99-96=3, the sequence moves 3 symbols onward, making symbol c fall on the 99th place.

Jacqueline M, Leytonstome E11
The pattern is repetitive by 4 each time
so pattern 100 would be the same pattern as pattern 4
so 99 is the same pattern as pattern 3.

Anna D, Oxford OX3
99 divided by 4 (as there are 4 symbols) = 24 remainder 3.
Therefore the 99th shape will be the third one in the series,
which is the box that has a horizontal line split through it.

Helen N, West Wimbledon, SW20:
The shapes are in groups of 4.
To find the 99th shape I used 4x20=80, then 4x5=20,
so I knew that 4 went into 100 and that the 99th shape
was the third shape in the sequence of 4.