Math Problem Statement

James has a job mowing lawns that pays $5 per hour. He also has a job at a clothing store that pays $8 per hour. He needs to earn at least $56 per week but can work less than 10 hours a week. The system below represents this scenario, where x represents the number of hours he works mowing lawns and y the number of hours he works at the clothing store.

x + y < 10

5x + 8y ≥ 56

Which statements describe a combination of hours James can work mowing lawns and at the clothing store?

Select TWO correct responses. A.James can work 3 hours mowing lawns and 5 hours at the clothing store. B.James can work 5 hours mowing lawns and 3 hours at the clothing store. C.James can work 2 hours mowing lawns and 7 hours at the clothing store. D.James can work 4 hours mowing lawns and 5 hours at the clothing store. E.James can work 8 hours mowing lawns and 2 hours at the clothing store.

Solution

To find which combinations of hours James can work, let's evaluate each option against both constraints:

  1. Total Hours Constraint:
    x+y<10x + y < 10 — James can work less than 10 hours in total.

  2. Earnings Constraint:
    5x+8y565x + 8y \geq 56 — James needs to earn at least $56 per week.

Now, we will test each option:

Option A: x=3x = 3, y=5y = 5

  • Total Hours Check: x+y=3+5=8x + y = 3 + 5 = 8, which is less than 10 (satisfies the first constraint).
  • Earnings Check: 5x+8y=5(3)+8(5)=15+40=555x + 8y = 5(3) + 8(5) = 15 + 40 = 55, which is less than 56 (does not satisfy the second constraint).
  • Conclusion: Not a valid option.

Option B: x=5x = 5, y=3y = 3

  • Total Hours Check: x+y=5+3=8x + y = 5 + 3 = 8, which is less than 10 (satisfies the first constraint).
  • Earnings Check: 5x+8y=5(5)+8(3)=25+24=495x + 8y = 5(5) + 8(3) = 25 + 24 = 49, which is less than 56 (does not satisfy the second constraint).
  • Conclusion: Not a valid option.

Option C: x=2x = 2, y=7y = 7

  • Total Hours Check: x+y=2+7=9x + y = 2 + 7 = 9, which is less than 10 (satisfies the first constraint).
  • Earnings Check: 5x+8y=5(2)+8(7)=10+56=665x + 8y = 5(2) + 8(7) = 10 + 56 = 66, which is greater than 56 (satisfies the second constraint).
  • Conclusion: Valid option.

Option D: x=4x = 4, y=5y = 5

  • Total Hours Check: x+y=4+5=9x + y = 4 + 5 = 9, which is less than 10 (satisfies the first constraint).
  • Earnings Check: 5x+8y=5(4)+8(5)=20+40=605x + 8y = 5(4) + 8(5) = 20 + 40 = 60, which is greater than 56 (satisfies the second constraint).
  • Conclusion: Valid option.

Option E: x=8x = 8, y=2y = 2

  • Total Hours Check: x+y=8+2=10x + y = 8 + 2 = 10, which is not less than 10 (does not satisfy the first constraint).
  • Earnings Check: Not needed, as it already fails the total hours constraint.
  • Conclusion: Not a valid option.

Answer:

The two correct responses are:

  • C. James can work 2 hours mowing lawns and 7 hours at the clothing store.
  • D. James can work 4 hours mowing lawns and 5 hours at the clothing store.

Would you like further details or have any questions?


Follow-up questions:

  1. How would the answer change if James’s earnings goal increased to $60 per week?
  2. If James could work up to 12 hours per week, would any additional options become valid?
  3. What if James's clothing store job started paying $10 per hour? How would this affect possible combinations?
  4. How would the scenario change if James could only work a maximum of 4 hours at each job?
  5. Could James work only at the clothing store to meet his earnings goal?

Tip: When working with inequalities, testing each condition separately can simplify finding valid solutions.

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Math Problem Analysis

Mathematical Concepts

Linear Inequalities
Systems of Inequalities

Formulas

x + y < 10
5x + 8y ≥ 56

Theorems

Solution of Systems of Linear Inequalities

Suitable Grade Level

Grades 8-10