SAT · Math —

Heart of Algebra appeared 17 times across 1 year — 100% of Math. This question is from Interpreting Linear Functions.

Year 2023 Total
Questions 17 17

In a factory, the number of units manufactured in a month follows the linear function N = 231D, where N is the number of units produced in the month and D is the number of days elapsed in the month. Which of the following represents 231 in the above equation?

Solution & Explanation

Related Formula

N = mD

where m represents the rate of unit production per day.

Core Logic

Evaluate N for successive values of D: For D = 1, N = 231. For D = 2, N = 462.

Each elapsed day adds 231 units to total production.

Step 1: Conclusion

Thus, 231 represents the number of units manufactured each day of the month (Option C).

Pattern Recognition

Linear multiplier of time variable arrow represents daily rate.

Chapter Mix

SAT Math: Heart of Algebra

Reference Study Guides

More Heart of Algebra Previous-Year Questions — Page 4

Q16 sat_math_2023_01_january_morning Solving Systems of Linear Equations
Using the following equation, what value of A makes the following system of equations have (-(4)/(7), -(1)/(7)) as a solution? Ax + 5y = -3 -8x + Ay = 4
  • A. 3
  • B. 5
  • C. 4
  • D. -4

Solution

Related Formula

A point (x₀, y₀) is a solution to a system of equations if substituting (x₀, y₀) into each equation yields a true identity.

Core Logic

Substitute x = -(4)/(7) and y = -(1)/(7) into Ax + 5y = -3:

A(-(4)/(7)) + 5(-(1)/(7)) = -3 -(4A)/(7) - (5)/(7) = -3

Multiply by 7:

-4A - 5 = -21 -4A = -16 A = 4
Step 1: Verification in Second Equation

Check A = 4 in -8x + Ay = 4:

-8(-(4)/(7)) + 4(-(1)/(7)) = (32 - 4)/(7) = (28)/(7) = 4 (Verified)

Thus, A = 4 (Option C).

Pattern Recognition

Given solution point (x, y) arrow substitute directly into linear equation to solve for unknown parameter A.

Chapter Mix

SAT Math: Heart of Algebra

Q17 sat_math_2023_01_january_morning Systems of Linear Inequalities
Choose the answer choice that best graphically displays the following equations: y < 2x + 4 y ≥ -(1)/(3)x - 2
  • A. A
  • B. B
  • C. C
  • D. D

Solution

Related Formula

For y < mx + b, boundary is dashed, shading is below. For y ≥ mx + b, boundary is solid, shading is above.

Core Logic

Analyze boundary line 1: y = 2x + 4

  • Dashed line with y-intercept (0, 4) and positive slope 2.
  • y < 2x + 4 shade BELOW the dashed line.
  • Analyze boundary line 2: y = -(1)/(3)x - 2

  • Solid line with y-intercept (0, -2) and negative slope -(1)/(3).
  • y ≥ -(1)/(3)x - 2 shade ABOVE the solid line.
Step 1: Select Matching Graph

Graph A correctly shows shading above the solid line y = -(1)/(3)x - 2 and below the dashed line y = 2x + 4.

Hence, choice A is correct.

Pattern Recognition

Dashed vs. solid line test arrow strict inequality (<) requires dashed; non-strict (≥) requires solid.

Chapter Mix

SAT Math: Heart of Algebra

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