If four numbers 1, 1/2, 1/3, 1/5 are proportional then x=

Option c: 15/2. Solution: The question text contains a typographical error in the representation of the four proportional numbers. The actual four numbers in proportion are 1/2, 1/3, 1/5, and 1/x . By the definition of proportion, if four numbers A, B, C, D are in proportion, then: A/B = C/D Here, we have: A = 1/2, B = 1/3, C = 1/5, D = 1/x Substituting these values into the proportion equation: 1/21/3 = 1/51/x Simplify both sides of the equation: - Left-hand side (LHS): 1/21/3 = 1/2 × 3/1 = 3/2 - Right-hand side (RHS): 1/51/x = 1/5 × x/1 = x/5 Now, equate LHS and RHS: 3/2 = x/5 Multiply both sides by 5 to solve for x : x = 3 × 5/2 = 15/2 This matches Option C. Hence, Option C is the correct answer.

Ratio, Proportion, Indices, LogarithmMCQMTP Dec 2023 Series IIQuestion 862 of 305

All Questions

If four numbers $\displaystyle 1, \frac{1}{2}, \frac{1}{3}, \frac{1}{5}$ are proportional then $\displaystyle x=$

Options

\displaystyle 6

\displaystyle 5

\displaystyle 15/2

DNone of these

For any discrepancies in this question, email contact@cadada.in

Correct Answer

✅ Option c — $\displaystyle 15/2$

All Options:

A $\displaystyle 6$
B $\displaystyle 5$
C $\displaystyle 15/2$
DNone of these

Detailed Solution & Explanation

The question text contains a typographical error in the representation of the four proportional numbers. The actual four numbers in proportion are

\displaystyle \frac{1}{2}, \frac{1}{3}, \frac{1}{5},

and

\displaystyle \frac{1}{x}

.
By the definition of proportion, if four numbers

\displaystyle A, B, C, D

are in proportion, then:

\frac{A}{B} = \frac{C}{D}

Here, we have:

A = \frac{1}{2}, \quad B = \frac{1}{3}, \quad C = \frac{1}{5}, \quad D = \frac{1}{x}

Substituting these values into the proportion equation:

\frac{\frac{1}{2}}{\frac{1}{3}} = \frac{\frac{1}{5}}{\frac{1}{x}}

Simplify both sides of the equation:
- Left-hand side (LHS):

\displaystyle \frac{\frac{1}{2}}{\frac{1}{3}} = \frac{1}{2} \times \frac{3}{1} = \frac{3}{2}

- Right-hand side (RHS):

\displaystyle \frac{\frac{1}{5}}{\frac{1}{x}} = \frac{1}{5} \times \frac{x}{1} = \frac{x}{5}

Now, equate LHS and RHS:

\frac{3}{2} = \frac{x}{5}

Multiply both sides by

\displaystyle 5

to solve for

\displaystyle x

x = \frac{3 \times 5}{2} = \frac{15}{2}

This matches **Option C**.
Hence, **Option C** 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.

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If four numbers 1,12,13,15\displaystyle 1, \frac{1}{2}, \frac{1}{3}, \frac{1}{5}1,21​,31​,51​ are proportional then x=\displaystyle x=x=