Dimensions Math 7B · Chapter 11

Inequalities
Mastery Quiz

20 carefully crafted problems — from word translations to real-world models. Tricky traps included.

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Part 1 — Translate Words into Inequalities
01
TranslationEasy

Which inequality represents: "5 less than a number \(x\) is greater than 12"?

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Memory Key: "Less than" ≠ subtract left "5 less than x" → start with x, then subtract 5 → \(x - 5\). Don't flip it to \(5 - x\)!
A \(5 - x > 12\)
B \(x - 5 > 12\)
C \(x + 5 > 12\)
D \(x - 5 \geq 12\)
02
TranslationTricky

Translate: "3 more than twice a number \(n\) is at most 15".

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Memory Key: "At most" = ≤ At most = maximum = can be equal or less → use ≤. "At least" = minimum = ≥.
A \(2n + 3 \leq 15\)
B \(2n + 3 < 15\)
C \(3n + 2 \leq 15\)
D \(2n + 3 \geq 15\)
03
TranslationHard

Which inequality matches: "The quotient of \(x\) and 4, decreased by 1, is no less than 7"?

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Memory Key: "No less than" = ≥ "No less than 7" means it cannot go below 7 → use ≥. Same as "at least".
A \(\dfrac{x}{4} - 1 > 7\)
B \(\dfrac{4}{x} - 1 \geq 7\)
C \(\dfrac{x}{4} - 1 \geq 7\)
D \(\dfrac{x - 1}{4} \geq 7\)
04
TranslationTricky

Which of the following is NOT equivalent to "x is no more than 9"?

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Memory Key: "No more than" synonyms "No more than", "at most", "does not exceed", "maximum" → all mean ≤.
A \(x \leq 9\)
B \(x\) does not exceed 9
C \(x < 9\)
D The maximum value of \(x\) is 9
05
TranslationHard

Translate: "Half of the sum of \(x\) and 6 is less than 10".

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Memory Key: "Half of the SUM" → parentheses! You add first, then divide. \(\frac{1}{2}(x+6)\) ≠ \(\frac{x}{2} + 6\)
A \(\dfrac{x}{2} + 6 < 10\)
B \(\dfrac{1}{2}(x + 6) < 10\)
C \(\dfrac{1}{2}(x + 6) \leq 10\)
D \(x + 6 < 5\)
Part 2 — Real-World Inequality Models
06
Real WorldVariable

A sign says: "Maximum capacity: 300 people."
Let \(p\) = number of people in the building. Which inequality models this?

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Memory Key: "Maximum" → ≤ (can equal max) Maximum 300 means you can have exactly 300, but not 301. Equal IS allowed → ≤.
A \(p < 300\)
B \(p \leq 300\)
C \(p \geq 300\)
D \(p = 300\)
07
Real WorldTricky

A roller coaster requires riders to be at least 48 inches tall.
Let \(h\) = a rider's height. Which inequality AND variable definition is correct?

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Memory Key: "At least" = minimum = ≥ At least 48" → \(h \geq 48\). The height must be 48 or taller.
A Let \(h\) = height in cm; \(\;h \geq 48\)
B Let \(h\) = height in inches; \(\;h \geq 48\)
C Let \(h\) = height in inches; \(\;h > 48\)
D Let \(h\) = height in inches; \(\;h \leq 48\)
08
Real WorldHard

Maria wants to spend less than $50 total. She already spent $18. Let \(m\) = remaining amount she can spend. Which inequality models this?

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Memory Key: total = already spent + remaining Set up: \(18 + m < 50\), or solve directly: \(m < 32\).
A \(m < 50\)
B \(m < 32\)
C \(m \leq 32\)
D \(m + 50 < 18\)
09
Real WorldHard

A speed limit sign says 65 MPH. A car is traveling at speed \(s\). Which inequality correctly models a car that is breaking the speed limit?

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Memory Key: "Breaking" = going over = STRICT > Legal speed: \(s \leq 65\). Breaking the limit: \(s > 65\) (strictly greater).
A \(s \leq 65\)
B \(s \geq 65\)
C \(s > 65\)
D \(s < 65\)
10
Real WorldVariable

A student needs at least 90 points to get an A. She scored 87 on her first test. Let \(s\) = her second test score needed (average of 2 tests). Which models the requirement?

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Memory Key: Average = sum ÷ count Average of 2 tests: \(\frac{87 + s}{2} \geq 90\)
A \(87 + s \geq 90\)
B \(\dfrac{87 + s}{2} \geq 90\)
C \(\dfrac{87 + s}{2} > 90\)
D \(s \geq 90\)
Part 3 — Solving One-Step Inequalities
11
SolvingAdd/Subtract

Solve: \(x + 7 < 3\)

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Memory Key: Add/Subtract → sign stays same Subtract 7 from both sides. The inequality direction does NOT flip.
A \(x < 10\)
B \(x > -4\)
C \(x < -4\)
D \(x \leq -4\)
12
SolvingFlip the Sign!

Solve: \(-3x \geq 12\)

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🔥 Memory Key: FLIP when dividing/multiplying by NEGATIVE! Divide both sides by −3 → inequality flips from ≥ to ≤. This is the #1 most common mistake!
A \(x \geq -4\)
B \(x \leq 4\)
C \(x \geq 4\)
D \(x \leq -4\)
13
SolvingDivide

Solve: \(\dfrac{x}{5} \leq -2\)

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Memory Key: Multiply by POSITIVE → no flip Multiply both sides by 5 (positive). Sign stays ≤.
A \(x \leq -7\)
B \(x \leq -10\)
C \(x \geq -10\)
D \(x \leq 10\)
14
SolvingNegative Multiply

Solve: \(-\dfrac{x}{4} > 3\)

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🔥 Memory Key: FLIP when multiplying by −4 Multiply both sides by −4 → flip > to <. Result: \(x < -12\).
A \(x < -12\)
B \(x > -12\)
C \(x > 12\)
D \(x < 12\)
15
SolvingTwo-Step

Solve: \(2x + 3 > 11\)

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Memory Key: Two-step → undo addition FIRST, then division Step 1: subtract 3 → \(2x > 8\). Step 2: divide by 2 (positive, no flip) → \(x > 4\).
A \(x > 7\)
B \(x > 4\)
C \(x \geq 4\)
D \(x < 4\)
Part 4 — Number Line Interpretation
16
GraphOpen/Closed

A number line shows a closed circle at 3, shading to the right. Which inequality does this represent?

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Memory Key: Open = strict (< or >), Closed = equal included (≤ or ≥) Closed dot = the number IS included = ≥ or ≤.
A \(x > 3\)
B \(x \geq 3\)
C \(x \leq 3\)
D \(x < 3\)
17
GraphTricky

Which value is NOT a solution of \(x \leq -2\)?

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Memory Key: Substitute to test! Plug each option into \(x \leq -2\). If the statement is FALSE, that's your answer.
A \(-5\)
B \(-2\)
C \(-10\)
D \(0\)
18
GraphHard

After solving \(5 - 2x > 9\), you graph the solution on a number line. Which description is correct?

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🔥 Remember: Solve first, FLIP when dividing by negative! \(5 - 2x > 9\) → \(-2x > 4\) → divide by −2, flip → \(x < -2\). Open circle at −2, shade LEFT.
A Open circle at \(-2\), shading to the right
B Closed circle at \(-2\), shading to the left
C Open circle at \(-2\), shading to the left
D Open circle at \(2\), shading to the left
Part 5 — Challenge & Mixed Problems
19
ChallengeWord Problem

A taxi charges a flat fee of $3 plus $2 per mile. Jenna has at most $15 to spend. What is the maximum number of miles she can ride? Set up the inequality.

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Memory Key: flat fee + rate × miles ≤ budget \(3 + 2m \leq 15\) → \(2m \leq 12\) → \(m \leq 6\). She can ride at most 6 miles.
A \(2m \leq 15\), so \(m \leq 7.5\)
B \(3 + 2m \leq 15\), so \(m \leq 6\)
C \(3 + 2m < 15\), so \(m < 6\)
D \(3m + 2 \leq 15\), so \(m \leq \frac{13}{3}\)
20
ChallengeBoss Level

Which of the following inequalities has the solution \(x > -3\)?

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Memory Key: Work backwards — substitute \(x = -3\) as boundary test Try \(x = 0\) (should work) and \(x = -5\) (should NOT work) in each option to verify.
A \(-2x > 6\)
B \(-2x < 6\)
C \(2x < -6\)
D \(2x > -6\)
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