Competition problem — Algebra — Maths Olympiad Prep

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Algebra Difficulty 2.1 Junior Find the answer

If $2n + 5 = 16$ , what is the value of the expression $2n - 3$ ?

Your answer

A number or a short expression. Spacing and $ signs are ignored.

Solution

Since $2n + 5 = 16$ , then $2n - 3 = (2n + 5) - 8 = 16 - 8 = 8$ . Alternatively, we could solve the equation $2n + 5 = 16$ to obtain $2n = 11$ or $n = \frac{11}{2}$ . From this, we see that $2n - 3 = 2\left(\frac{11}{2}\right) - 3 = 11 - 3 = 8$ .

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