Linear inequality word problems

How the SAT tests this, with worked examples — plus the 2 skills it covers. Free to read, no account needed.

These are linear word problems whose answer is a range rather than a single value. The modelling is identical; the extra step is turning a phrase into the right inequality sign.
et_inequality_words.png
The distinction that matters is whether the boundary value itself counts. At least and no more than include it, giving ≥\geq and ≤\leq. More than and fewer than exclude it, giving >> and <<.
So "a budget of at most $200\$200" becomes cost≤200\text{cost} \leq 200, while "more than 10 attendees" becomes n>10n > 10.
Solve exactly as you would an equation, with one exception: multiplying or dividing by a negative number flips the sign.
Finally, check the answer against the situation. Counts of people or items must be whole numbers, so a solution of n>10.4n > 10.4 means 1111 or more — and the answer choices will include 10.410.4 for anyone who stops at the algebra.

Worked examples

Tickets cost $15\$15 each and the budget is at most $200\$200. How many can be bought?
At most includes the boundary
15n≤200  ⇒  n≤13.33{15n \leq 200 \;\Rightarrow\; n \leq 13.33}
Tickets are whole, so at most 1313.
A van holds more than 88 boxes but no more than 1515. Write this as an inequality.
More than excludes 88; no more than includes 1515
8<b≤15{8 < b \leq 15}

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All the skills in Linear inequality word problems