Ratio, Proportion, Indices, LogarithmMCQPYQ Dec 23Question 891 of 305
All Questions

If 9n×35×(27)53×(81)4=27\displaystyle \frac{9^n \times 3^5 \times (27)^5}{3 \times (81)^4} = 27, then the value of n\displaystyle n is

Options

A2
B0
C3
D4
For any discrepancies in this question, email contact@cadada.in

Correct Answer

Option b0

All Options:

  • A2
  • B0
  • C3
  • D4

Ad

Detailed Solution & Explanation

Given the equation:
9n×35×(27)53×(81)4=27\frac{9^n \times 3^5 \times (27)^5}{3 \times (81)^4} = 27
Let us express all terms with base 3\displaystyle 3 using the laws of exponents:
- 9n=(32)n=32n\displaystyle 9^n = (3^2)^n = 3^{2n}
- 275=(33)5=315\displaystyle 27^5 = (3^3)^5 = 3^{15}
- 814=(34)4=316\displaystyle 81^4 = (3^4)^4 = 3^{16}
- 27=33\displaystyle 27 = 3^3
Substitute these expressions back into the original equation:
32n×35×3153×316=33\frac{3^{2n} \times 3^5 \times 3^{15}}{3 \times 3^{16}} = 3^3
Simplify the numerator using xaxb=xa+b\displaystyle x^a \cdot x^b = x^{a+b}:
Numerator=32n+5+15=32n+20\text{Numerator} = 3^{2n + 5 + 15} = 3^{2n + 20}
Simplify the denominator:
Denominator=31×316=317\text{Denominator} = 3^1 \times 3^{16} = 3^{17}
Now divide the numerator by the denominator:
32n+20317=32n+2017=32n+3\frac{3^{2n+20}}{3^{17}} = 3^{2n + 20 - 17} = 3^{2n+3}
Equate this to the right-hand side (33\displaystyle 3^3):
32n+3=333^{2n+3} = 3^3
Since the bases are identical, we equate the exponents:
2n+3=32n + 3 = 3
2n=0    n=02n = 0 \implies n = 0
This matches **Option B**.
Hence, **Option B** is the correct answer.

About This Chapter: Ratio, Proportion, Indices, Logarithm

Paper

Paper 3: Quantitative Aptitude

Weightage

5-7 Marks

Key Topics

Ratio, Proportion, Indices, Logarithms

This chapter covers Ratio, Proportion, Indices, Logarithms and is part of Paper 3: Quantitative Aptitude in the CA Foundation exam.

View Official ICAI Syllabus

Exam Strategy Tip

This topic carries 5-7 Marks weightage. Focus on understanding core concepts rather than memorizing.

More Questions from Ratio, Proportion, Indices, Logarithm

Ready to Master Ratio, Proportion, Indices, Logarithm?

Practice all 305 questions with instant feedback, earn XP, track your streaks, and ace your CA Foundation exam.

Start Practicing — It's Free