Example

Translating a Combined-Earnings Word Problem into a System of Equations

Apply the first four steps of the problem-solving strategy for systems of linear equations to translate a real-world earnings problem into a system without solving it.

Problem: A married couple together earns $110,000 a year. The wife earns $16,000 less than twice what her husband earns. What does the husband earn?

  1. Identify what to find: the amount that the husband and wife each earn.
  2. Name the unknowns: Let hh = the amount the husband earns and ww = the amount the wife earns.
  3. Translate each verbal relationship into an equation:
    • "A married couple together earns $110,000" translates to w+h=110,000w + h = 110{,}000.
    • "The wife earns $16,000 less than twice what her husband earns" translates to w=2h16,000w = 2h - 16{,}000.
  4. The resulting system is:

{w+h=110,000w=2h16,000\left\{\begin{array}{l} w + h = 110{,}000 \\ w = 2h - 16{,}000 \end{array}\right.

Compare this with the single-variable approach to the same problem, where the wife's earnings must be expressed as 2h16,0002h - 16{,}000 and then substituted into a single equation h+(2h16,000)=110,000h + (2h - 16{,}000) = 110{,}000. The systems approach lets each person's earnings keep its own variable, making the initial setup more direct — each fact in the problem becomes its own equation.

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Updated 2026-04-21

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