Create linear equations from a context/word problem and interpret the solution.
Translate the situation into an equation, solve it, and interpret the result in context.
核心知识
Translate word problems into equations by identifying the unknown (variable), the rates or per-unit quantities (coefficients), and the fixed amounts (constants), then solve and state what the answer means in context.
深入理解
Word problems follow a pattern: a situation is described, and you need to find an unknown quantity. Start by deciding what the variable represents — write it down explicitly, like "let
Next, build the equation from the relationships in the problem. Look for signal phrases: "per" or "each" signals multiplication (a rate × the variable). "Total," "combined," or "altogether" signals the sum of all parts. "More than" or "less than" signals addition or subtraction.
After solving, interpret the solution in the context of the problem. The SAT frequently makes one of the answer choices the correct numerical value but with the wrong interpretation, so read carefully.
A useful check: does your answer make sense? If
分步讲解
- Define the variable — write what it represents in the context of the problem.
- Identify rates, fixed amounts, and totals from the problem description.
- Translate the relationships into an equation.
- Solve the equation and interpret the result in context.
常见误解
- Setting up the equation with the wrong operation — using addition when the problem describes a per-unit rate (which requires multiplication).
- Solving correctly but choosing an answer that misinterprets what the variable represents.
- Forgetting to account for all parts of the problem — for example, ignoring a starting amount or fixed cost.
示例解析
Maria has $120 and saves $25 each week. After how many weeks will she have $345?
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