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All numbers in the first column have been increased by the same percentage, to give the results shown in the second column.
A given letter stands for the same numeral every time it appears in that column, so for example, whatever the C stands for, it stands for that numeral every time the C appears.
Can you work out the percentage increase?
What about this next set?
It's a new coding - the letters now stand for different numerals.
What percentage have the numbers in the first column been increased by this time?
Can you work out the percentage increase here?
Different coding again, and much harder...