Equations and Inequalities
Help Questions
DAT Quantitative Reasoning › Equations and Inequalities
A dentist mixes $x$ mL of fluoride concentrate at $\$0.40$/mL plus $$5$ bottle cost; if total is $\$21$, solve $0.40x+5=21$ for $x$.
$x=42$
$x=45$
$x=40$
$x=38$
$x=35$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves mixing fluoride concentrate with a bottle cost, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, x=40, is obtained by subtracting 5 from both sides to get 0.40x=16, then dividing by 0.40. A common mistake is x=38, which results from rounding errors or miscalculating 0.40*38 +5 as 21 instead of 20.2. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.
A hygiene kit costs $\$25$ plus $$3$ per disposable item; if total is $\$55$, solve $25+3x=55$ for $x$.
$x=11$
$x=12$
$x=9$
$x=8$
$x=10$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves calculating disposable items in a hygiene kit with a base cost, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, x=10, is obtained by subtracting 25 from both sides to get 3x=30, then dividing by 3. A common mistake is x=9, which results from subtracting incorrectly to get 3x=27 instead of 30. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.
A dental lab charges $\$120$ setup plus $$15$ per crown; if total is $\$345$, solve $120+15x=345$ for $x$.
$x=13$
$x=14$
$x=15$
$x=16$
$x=17$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves calculating the number of crowns based on a setup fee and per-crown cost, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, x=15, is obtained by subtracting 120 from both sides to get 15x=225, then dividing by 15. A common mistake is x=14, which results from miscalculating 15*14 +120 as 345 instead of 330. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.
A culture from dental plaque triples every day; if $N(t)=80\cdot3^t$, what is $N(2)$ after $2$ days?
$N(2)=1{,}440$
$N(2)=720$
$N(2)=960$
$N(2)=240$
$N(2)=360$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves predicting bacteria in dental plaque over days, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, N(2)=720, is obtained by substituting t=2 into $803^2$ and calculating 809. A common mistake is N(2)=360, which results from multiplying by 3 instead of $3^2$. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.
A dental lab bills $\$90$ base plus $$12$ per model; if total is $\$210$, solve $90+12x=210$ for $x$.
$x=9$
$x=8$
$x=12$
$x=10$
$x=11$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves determining the number of models in a dental lab bill, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, x=10, is obtained by subtracting 90 from both sides to get 12x=120, then dividing by 12. A common mistake is x=9, which results from miscalculating 12*9 +90 as 210 instead of 198. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.
A clinic budgets $\$600$–$$900$ for masks; which is the solution set for $600\le 30x+120\le 900$?
$16\le x\le 26$
$26\le x\le 16$
$20\le x\le 26$
$14\le x\le 26$
$16\le x\le 28$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves a clinic budgeting for masks, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, 16≤x≤26, is obtained by subtracting 120 from all parts and dividing by 30. A common mistake is 14≤x≤26, which results from miscalculating the lower bound. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.
A dental practice budgets $\$2{,}200$–$$2{,}800$ for software; which is the solution set for $2200\le 150x+850\le 2800$?
$8\le x\le 13$
$13\le x\le 9$
$10\le x\le 13$
$9\le x\le 13$
$9\le x\le 14$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves budgeting for dental practice software, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, 9≤x≤13, is obtained by subtracting 850 from all parts and dividing by 150. A common mistake is 8≤x≤13, which results from lowering the lower bound incorrectly. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.
A new dental office budgets $\$4{,}000$ to $$5{,}200$ for chairs; which represents $4000\le 800x+800\le 5200$ solution set?
$4\le x\le 5.5$
$3\le x\le 6$
$5.5\le x\le 6$
$4\le x\le 6$
$3\le x\le 5.5$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves budgeting for dental office chairs within a range, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, 4≤x≤5.5, is obtained by subtracting 800 from all parts and dividing by 800. A common mistake is 4≤x≤6, which results from incorrect division or boundary miscalculation. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.
A disinfectant-resistant strain grows by factor $1.1$ per hour; if $N(t)=900(1.1)^t$, what is $N(3)$?
$N(3)=1{,}331.0$
$N(3)=1{,}089.0$
$N(3)=990.0$
$N(3)=1{,}209.0$
$N(3)=1{,}197.9$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves predicting growth of a disinfectant-resistant bacteria strain, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, N(3)=1,197.9, is obtained by substituting t=3 into $900*(1.1)^3$ and calculating 900*1.331. A common mistake is N(3)=1,089.0, which results from using $(1.1)^2$ instead of ^3. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.
Bacteria on a mouthguard increases $20%$ per hour; if $N(t)=500(1.2)^t$, what is $N(2)$?
$N(2)=750$
$N(2)=720$
$N(2)=600$
$N(2)=650$
$N(2)=700$
Explanation
This question tests the ability to solve algebraic equations and inequalities involving linear, quadratic, and exponential expressions, essential for dental quantitative reasoning. Algebra involves manipulating equations and inequalities to find unknown values, using techniques such as substitution, elimination, and the quadratic formula. In this question, the scenario involves modeling bacteria increase on a mouthguard, requiring the application of algebraic principles to solve for the unknown variable. The correct answer, N(2)=720, is obtained by substituting t=2 into $500*(1.2)^2$ and calculating 500*1.44. A common mistake is N(2)=700, which results from adding 20% twice incorrectly instead of compounding. To improve, students should practice setting up equations based on real-world scenarios and verify each step of their solution process, using checks like substituting back into the original equation to ensure accuracy.