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CEMC Cayley

Algebra Difficulty 1.9 Junior Find the answer

When a number is tripled and then decreased by 5, the result is 16. What is the original number?

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

Solution

To get back to the original number, we undo the given operations. We add 5 to 16 to obtain 21 and then divide by 3 to obtain 7. These are the 'inverse' operations of decreasing by 5 and multiplying by 3.

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