Sophia thinks of a number.
She then does the following operations:
Multiply by 3, subtract 4, multiply by 2 then add 29 (in that order).
She finds that the number she ends up with is 9 times her original number.
What was Sophia's original number?
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This question is best answered by forming an algebraic equation then solving it. Let Sophia's original number be x.
First operation gives 3x
Second operation gives 3x 4
Third operation gives 2(3x 4)
Fourth operation gives 2(3x 4) + 29
This is equal to 9 times the original number
2(3x  4) + 29 = 9x
6x 8 + 29 = 9x
...
x = 7
Sophia's original number was 7.
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