Question Bank • QB_GA_ADV_121 MCQ • 1 Mark

Section 8: General Aptitude

Analytical & Spatial Aptitude

Subtopic: Logic Deduction & Pattern Recognition

Question Statement:

Find the next number in the sequence: $3,\; 8,\; 18,\; 38,\; 78,\; \underline{\hspace{1.5cm}}$

Options:

  • (A) $158$
  • (B) $156$
  • (C) $148$
  • (D) $168$

Answer Key:

A

Step-by-Step Solution & Explanation

**Method 1: Differences Pattern** - $8 - 3 = 5$ - $18 - 8 = 10$ - $38 - 18 = 20$ - $78 - 38 = 40$ The successive differences double each time ($5, 10, 20, 40, 80$). $\text{Next term} = 78 + 80 = 158$ **Method 2: Multiplicative Recurrence** $a_{n+1} = 2a_n + 2$ - $2(3) + 2 = 8$ - $2(8) + 2 = 18$ - $2(18) + 2 = 38$ - $2(38) + 2 = 78$ - $2(78) + 2 = 156 + 2 = 158$ Option **A** is correct.
← Previous (QB_GA_ADV_085) Next (QB_GA_ADV_123) →

Practice In Authentic CBT Exam Interface

Test your skills under authentic timed conditions with live scoring and AIR percentile ranking.

Launch CBT Mock Test