Grade 8 Math · Expressions & Equations

Model real situations with systems

Model real situations with systems.

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What you’ll learn

Model real situations with systems.

Key idea

A count total adds counts; a revenue total adds each count multiplied by its own category price.

Match count and dollar units; each variable retains its own price coefficient, with distinct prices ensuring a unique feasible pair.

Worked example

Enter the exact value or ordered values in the format requested below.

A show sells adult tickets at $8 and child tickets at $3; 10 tickets yield $40. Let x count adults and y count children. Write both modeling equations separated by a semicolon; no solution is required.

  1. x and y count adult and child tickets; their unweighted sum is x+y=10.
  2. Multiplying each category by its own dollar price gives 8x+3y=40; both count and money equations are needed.

Answer: x+y=10;8x+3y=40

Quick Check

Choose which candidate representation satisfies the requirements of 'Model real situations with systems' and justify the choice.

A show sells adult tickets at $8 and child tickets at $3; 7 tickets yield $51. Let x count adults and y count children. Select the system satisfying both constraints and justify the units.

Choose one answer

Show a hint

Keep the named variables attached to their ticket categories.