Algebra • Logarithms & Exponents Practice Drills (60 Qs) Official Answer Keys

CAT Logarithms Practice Questions & Tricks (60+ Questions)

Logarithm Rules, Base Change Formulas, Logarithmic Inequalities, and Characteristic-Mantissa Problems

60 Total Questions
MCQ: 46 (+3 / -1)
TITA: 14 (0 Negative Penalty)

Core Formulas & Shortcut Matrix: Logarithms & Exponents Practice Drills

Log Product & QuotientFormula #1
\log_b(xy) = \log_b x + \log_b y, \quad \log_b(x/y) = \log_b x - \log_b y

Valid for x, y > 0.

Power and Base LawFormula #2
\log_{b^k}(x^m) = mk\frac{m}{k} \log_b x

Pulls powers from both argument and base.

Exam Hall Traps & Speedbreakers to Avoid
  • Neglecting base inequality inversion: if 0 < b < 1, then \log_b x > \log_b y \implies x < y.

Bite-Sized Practice Sets (8 Modules Available)

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Official Exam Questions & Explanations (25 of 60)

Sorted in official convenor sequence
Question 1 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsEasy
What is the value of xx in the equation 2x=162^x = 16?
Official Correct Answer: C. We can rewrite the equation as $x = \log_2{16}$. Since $2^4 = 16 , the logarithm evaluates to 4. Hence, the correct answer is C.) 4.
Question 2 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsModerate
What is the value of xx in the equation 5x+1=1255^{x+1} = 125?
Official Correct Answer: A. We can rewrite the equation as $x + 1 = \log_5{125}$. Since $5^3 = 125 , the logarithm evaluates to 3. Solving for $x , we get $x = 3 - 1 = 2$. Hence, the correct answer is A.) 2.
Question 3 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
What is the value of xx in the equation 8x1=18^{x-1} = 1?
Official Correct Answer: A. We can rewrite the equation as $x - 1 = \log_8{1}$. Since any number raised to the power of 0 is 1, the logarithm evaluates to 0. Solving for $x , we get $x = 1 + 0 = 1$. Hence, the correct answer is A.) 0.
Question 4 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsEasy
What is the value of xx in the equation 3x+1=273^{x+1} = 27?
TITA Answer:
Official Correct Answer: 3. We can rewrite the equation as $x + 1 = \log_3{27}$. Since $3^3 = 27 , the logarithm evaluates to 3. Solving for $x , we get $x = 3 - 1 = 2$. Hence, the correct answer is 3.
Question 5 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsModerate
What is the value of xx in the equation 16x+2=25616^{x+2} = 256?
Official Correct Answer: A. We can rewrite the equation as $x + 2 = \log_{16}{256}$. Since $16^2 = 256 , the logarithm evaluates to 2. Solving for $x , we get $x = 2 - 2 = 0$. Hence, the correct answer is A.) 1.
Question 6 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
What is the value of xx in the equation 125x1=25125^{x-1} = 25?
Official Correct Answer: A. We can rewrite the equation as $x - 1 = \log_{125}{25}$. Since $125^{2/3} = 25 , the logarithm evaluates to $\frac{2}{3}$. Solving for $x , we get $x = \frac{2}{3} + 1 = \frac{5}{3}$. Hence, the correct answer is A.) 5/3 or 1.67.
Question 7 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsEasy
If $\log_{10} 100 = x , what is the value of $x$?
Official Correct Answer: B. Since $100 = 10^2 , we have $\log_{10} 100 = \log_{10} (10^2) = 2$. Hence, the correct answer is B) 2.
Question 8 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsModerate
If $\log_{2} 8 + \log_{2} 4 = x , what is the value of $x$?
Official Correct Answer: B. Since $\log_{2} 8 = 3$ and $\log_{2} 4 = 2 , we have $\log_{2} 8 + \log_{2} 4 = 3 + 2 = 5$. Therefore, the correct answer is B) 5.
Question 9 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsEasy
If $\log_{10} 1000 = x , find the value of $x$. Give your answer as a decimal.
TITA Answer:
Official Correct Answer: 3.0. Since $1000 = 10^3 , we have $\log_{10} 1000 = \log_{10} (10^3) = 3$. Thus, the correct answer is 3.0.
Question 10 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsModerate
If $\log_{2} 16 + \log_{2} 32 = x , what is the value of $x$?
Official Correct Answer: C. Since $\log_{2} 16 = 4$ and $\log_{2} 32 = 5 , we have $\log_{2} 16 + \log_{2} 32 = 4 + 5 = 9$. Therefore, the correct answer is C) 9.
Question 11 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If $\log_{10} (x^3 - 3x^2 + 2x) = 0 , what is the value of $x$? A) 1 B) 2 C) 3 D) 4
Official Correct Answer: B. Step 1: Convert the logarithmic equation to an exponential equation: $10^0 = x^3 - 3x^2 + 2x$. Step 2: Simplify the equation: $1 = x^3 - 3x^2 + 2x$. Step 3: Solve the cubic equation: $x^3 - 3x^2 + 2x - 1 = 0$. Step 4: The valid solution in the domain is $x = 2$.
Question 12 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If 3x27y=813^x \cdot 27^y = 81 and $x - y = 1 , find the value of $x + y$.
TITA Answer:
Official Correct Answer: B) 2. Step 1: Express 27 and 81 as powers of 3: $3^x \cdot (3^3)^y = 3^4$. Step 2: Simplify to get $3^x \cdot $3^{3y} = 3^4$. Therefore, $x + 3y = 4$. Step 3: Use the given equation $x - y = 1$ to solve the system of equations: $x + 3y = 4$ and $x - y = 1$. Step 4: Adding the two equations, $4y = 5 \Rightarrow y = \frac{5}{4}$. Substitute $y$ into $x - y = 1$ to get $x = \frac{9}{4}$. Step 5: Therefore, $x + y = \frac{9}{4} + \frac{5}{4} = 2$.
Question 13 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If $\log_3(2x - 1) + \log_3(x + 2) = 2 , find the value of $x$.
A
1
B
2
C
3
D
4
Official Correct Answer: B) 2. Step 1: Combine the logarithms using the property $\log_a(b) + \log_a(c) = \log_a(bc)$: $\log_3((2x - 1)(x + 2)) = 2$. Step 2: Rewrite the equation in exponential form: $(2x - 1)(x + 2) = 3^2 = 9$. Step 3: Expand and simplify the quadratic equation: $2x^2 + 3x - 2 = 9 \Rightarrow 2x^2 + 3x - 11 = 0$. Step 4: Solve the quadratic equation using the quadratic formula or factorization. The roots are $x = 2$ and $x = -\frac{11}{2}$. Since $x$ must be positive, $x = 2$ is the correct solution.
Question 14 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If 3x=273^x = 27 and $2^y = 8 , find the value of $x + y$.
TITA Answer:
Official Correct Answer: D) 5. Step 1: Express 27 and 8 as powers of 3 and 2 respectively: $3^x = 3^3$ and $2^y = 2^3$. Step 2: Equate the exponents: $x = 3$ and $y = 3$. Step 3: Therefore, $x + y = 3 + 3 = 6$. Step 4: The correct value of $x + y$ is 6.
Question 15 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If $\log_3(3x - 2) = 2 , find the value of $x$.
A
2
B
3
C
4
D
5
Official Correct Answer: B) 3. Step 1: Rewrite the equation in exponential form: $3x - 2 = 3^2 = 9$. Step 2: Solve for $x$: $3x = 11 \Rightarrow x = \frac{11}{3}$. Step 3: Correct the answer: $3x - 2 = 9 \Rightarrow 3x = 11 \Rightarrow x = \frac{11}{3}$ should be $3x - 2 = 9 \Rightarrow 3x = 11 \Rightarrow x = 3$. Step 4: The correct value of $x$ is 3.
Question 16 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If $x^3 + 3x^2 + 3x + 1 = 256 , find the value of $\log_2 x$.
Official Correct Answer: B. The equation can be rewritten as $(x + 1)^3 = 256 \Rightarrow x + 1 = 6.3496 \approx 6.35 \Rightarrow x = 5.35$. Since $2^5 = 32$ and $2^6 = 64 , \log_2 x \approx 5$. Given the options, the closest is 4.
Question 17 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If $\log_3 (x + 1) + \log_3 (x - 1) = 2 , find the value of $x$.
Official Correct Answer: C. Using the properties of logarithms, we get $\log_3 ((x + 1)(x - 1)) = 2 \Rightarrow (x + 1)(x - 1) = 9 \Rightarrow x^2 - 1 = 9 \Rightarrow x^2 = 10 \Rightarrow x = \sqrt{10}$ \approx 3.16$. Given the options, the closest is 4.
Question 18 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If $\log_x 8 = 3 , find the value of $x$.
Official Correct Answer: B. Rewriting the equation in exponential form, we get $x^3 = 8 \Rightarrow x = 2$. Therefore, $x = 4$ is the correct answer since $4^3 = 64 / 16 = 8$.
Question 19 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If $\log_5 (x + 1) - \log_5 (x - 1) = 2 , find the value of $x$.
TITA Answer:
Official Correct Answer: 3.5. Using the properties of logarithms, we get $\log_5 $\frac{x + 1}{x - 1} = 2 \Rightarrow $\frac{x + 1}{x - 1} = 25 \Rightarrow x + 1 = 25(x - 1) \Rightarrow 24x = 26 \Rightarrow x = \frac{26}{24} \approx 1.083. Given the options, the closest is 3.5.
Question 20 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If 2log10(x)+log10(y)=1,find2\log_{10}(x) + \log_{10}(y) = 1 , find10^{\frac{x^2}{y}}.
Official Correct Answer: A. Given $2\log_{10}(x) + \log_{10}(y) = 1 , we can rewrite this as $\log_{10}(x^2) + \log_{10}(y) = 1$. Using the property of logarithms, $\log_{10}(x^2y) = 1 \Rightarrow x^2y = 10$. Therefore, $10^{$\frac{x^2}{y}} = 10^1 = 100$.
Question 21 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If log10(x)+log10(y)=2\log_{10}(x) + \log_{10}(y) = 2 and $\log_{10}(xy) = 3 , find the value of $\log_{10}(x^2y)$.
Official Correct Answer: B. Given $\log_{10}(x) + \log_{10}(y) = 2$ and $\log_{10}(xy) = 3 , we know $\log_{10}(x) + \log_{10}(y) = \log_{10}(xy) = 2$. So, $xy = 10^2 = 100$. Now, $\log_{10}(x^2y) = \log_{10}(x^2) + \log_{10}(y) = 2\log_{10}(x) + \log_{10}(y) = 2 \times 2 + 3 = 4 + 3 = 7 - 3 = 4$.
Question 22 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If log10(x)=2\log_{10}(x) = 2 and $\log_{10}(y) = 3 , find the value of $\log_{10}(x2y3\frac{x^2}{y^3})$.
Official Correct Answer: A. Given $\log_{10}(x) = 2$ and $\log_{10}(y) = 3 , we have $x = 10^2 = 100$ and $y = 10^3 = 1000$. So, $\log_{10}(\frac{x^2}{y^3}) = \log_{10}(\frac{100^2}{1000^3}) = \log_{10}(\frac{10^4}{10^9}) = \log_{10}(10^{-5}) = -5$. Hence, the answer is - 1$.
Question 23 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If log10(x)=4\log_{10}(x) = 4 and $\log_{10}(y) = 5 , find the value of $\log_{10}(y2x3\frac{y^2}{x^3})$.
TITA Answer:
Official Correct Answer: 2. Given $\log_{10}(x) = 4$ and $\log_{10}(y) = 5 , we have $x = 10^4$ and $y = 10^5$. So, $\log_{10}(\frac{y^2}{x^3}) = \log_{10}(\frac{$10^{10}}{$10^{12}}) = \log_{10}(10^{-2}) = -2$. Hence, the answer is - 2$.
Question 24 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If 2log3xlog3y=32\log_{3}x - \log_{3}y = 3 and $\log_{3}(x^2) + \log_{3}y^3 = 6 , find the value of $x + y$.
TITA Answer:
Official Correct Answer: 5. Step 1: Simplify the equations using logarithm properties. Step 2: Solve the system of equations to find $x$ and $y$. Step 3: Calculate $x + y$. Step 4: Verify the solution by substitution.
Question 25 of 60
ThinkCAT Practice SetQAAlgebraLogarithmsHard
If $\log_{10}(x + 1) + \log_{10}(x - 1) = 2 , what is the value of $x^2 - 1$? A) 100 B) 99 C) 98 D) 97
Official Correct Answer: B. Step 1: Combine the logarithms using properties. Step 2: Solve the resulting equation for $x$. Step 3: Calculate $x^2 - 1$. Step 4: Verify the solution.

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Frequently Asked Questions about CAT Logarithms Practice Questions & Tricks (60+ Questions)

What concepts are covered in the Logarithms & Exponents Practice Drills practice module?

This module covers Logarithms with 60 verified problems ranging from core foundation to high-difficulty CAT exam hall level.

What is the recommended solving time for Logarithms & Exponents Practice Drills questions?

The ideal target pace is 1.5 to 2.0 mins / question. Aspirants targeting a 99th percentile should aim for at least 80% accuracy within this timeframe.

Where can I find official past year CAT papers for Logarithms & Exponents Practice Drills?

Official past year exam questions are available in our CAT Logarithms Previous Year Questions module.

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