silemus.
← All examples
  1. 4Compound inequality
  2. 9Perpendicular line equation
  3. 12Two-variable ticket problem
  4. 13Equal cost of two plans
  5. 16Evaluating 16^(−3/4)
  6. 18Rationalising 6/root3
  7. 19Solving a square root equation
  8. 22Factoring 2x²+7x−15
  9. 25Completing the square
  10. 29Max height, projectile motion
  11. 32Composing f(g(2)), g(f(2))
  12. 33Inverse function value
  13. 36Compound interest formula
  14. 38Absolute value inequality
  15. 40Solving rational equation

13Equal cost of two plans

Plan A costs $25 a month plus $0.10 per minute. Plan B costs $40 a month with unlimited minutes. For how many minutes do the two plans cost the same?

The two plans cost the same at 150 minutes. Setting 25 + 0.10x equal to 40 gives 0.10x = 15, so x = 150. Check: 25 + 0.10(150) = 40, matching Plan B's flat rate.

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