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Algebra Difficulty 1.9 Junior Find the answer

The list p,q,r,sp, q, r, s consists of four consecutive integers listed in increasing order. If p+s=109p + s = 109, what is the value of q+rq + r?

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

Solution

Since p,q,r,sp, q, r, s is a list of consecutive integers in increasing order, then qq is 1 more than pp and rr is 1 less than ss. This means that q+r=(p+1)+(s1)=p+s=109q + r = (p + 1) + (s - 1) = p + s = 109. Therefore, q+r=109q + r = 109.

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