Number Series, Coding and DecodingMCQMTP June 24 Series IQuestion 2074 of 217
All Questions

Find next term of the series A5A, C10C, E15E, E20G ______.

Select Your Answer (Keyboard: A, B, C, D)
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Correct Answer

✅ Option a — I25I

All Options:

  • AI25I
  • BI20I
  • CJ25J
  • DK20K

Detailed Solution & Explanation

To find the next term of the series A5A,C10C,E15E,E20G,…\displaystyle A5A, C10C, E15E, E20G, \dots:

Let us analyze the three components of each term (first letter, central number, and last letter):

1. **First Letter Progression:**
- Letters: A→C→E→[G]…\displaystyle A →\displaystyle \to C →\displaystyle \to E →\displaystyle \to [G] \dots
- Alphabetical positions: 1→3→5→[7]…\displaystyle 1 →\displaystyle \to 3 →\displaystyle \to 5 →\displaystyle \to [7] \dots
- The pattern is an increase of +2\displaystyle +2 at each step. Thus, the 5th term should start with the 9th letter, which is **I**.
*Note:* The 4th term's first letter is printed as E\displaystyle E (in E20G\displaystyle E20G), which is a typographical error for G\displaystyle G in the question paper.

2. **Central Number Progression:**
- Numbers: 5→10→15→20…\displaystyle 5 →\displaystyle \to 10 →\displaystyle \to 15 →\displaystyle \to 20 \dots
- This is a simple arithmetic progression increasing by +5\displaystyle +5. Thus, the next number is:
20+5=2520 + 5 = 25
3. **Last Letter Progression:**
- Letters: A→C→E→G…\displaystyle A →\displaystyle \to C →\displaystyle \to E →\displaystyle \to G \dots
- Alphabetical positions: 1→3→5→7…\displaystyle 1 →\displaystyle \to 3 →\displaystyle \to 5 →\displaystyle \to 7 \dots
- This also increases by +2\displaystyle +2 at each step. The next letter (9th position) is **I**.

Combining the three components, the next term is **I25I**.

Hence, **Option A** is the correct answer.

About This Chapter: Number Series, Coding and Decoding

Paper

Paper 3: Quantitative Aptitude

Weightage

5 Marks

Key Topics

Number series, Coding & Decoding, Odd man out

This chapter covers Number series, Coding & Decoding, Odd man out and is part of Paper 3: Quantitative Aptitude in the CA Foundation exam.

View Official ICAI Syllabus

Exam Strategy Tip

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

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