Number Series & Quadratic Equations

What you'll learn

A from-scratch guide to two of the fastest-scoring topics in IBPS and SBI Prelims — the fixed order for testing number-series patterns (difference, product, square, cube, mixed) and the sign shortcut for comparing the roots of two quadratics (x vs y), with fully worked examples and the common "greater-than-or-equal vs strictly-greater" and "no relation" traps.

This chapter has

Number Series & Quadratic Equations — solved practice questions

8 Banking Quantitative Aptitude questions with step-by-step solutions. Attempt each, then reveal the answer.

1. Q1easy

   Find the next term in the series: 2, 6, 12, 20, 30, ?

   • A40
   • B42
   • C44
   • D46
   Show answer & solution

   Correct answer: (B) 42

   The differences increase by 2 (4, 6, 8, 10, 12), so the next term is 30 + 12 = 42.

2. Q2easy

   Find the next term in the series: 3, 6, 12, 24, 48, ?

   • A96
   • B84
   • C108
   • D90
   Show answer & solution

   Correct answer: (A) 96

   Each term is double the previous one, so 48 × 2 = 96.

3. Q3medium

   Find the next term in the series: 5, 11, 23, 47, 95, ?

   • A181
   • B190
   • C191
   • D201
   Show answer & solution

   Correct answer: (C) 191

   Each term follows the rule ×2 + 1, so 95 × 2 + 1 = 191.

4. Q4easy

   Find the next term in the series: 1, 4, 9, 16, 25, ?

   • A30
   • B35
   • C49
   • D36
   Show answer & solution

   Correct answer: (D) 36

   These are perfect squares (1², 2², 3², 4², 5²), so the next is 6² = 36.

5. Q5easy

   Find the next term in the series: 7, 14, 28, 56, ?

   • A112
   • B98
   • C120
   • D104
   Show answer & solution

   Correct answer: (A) 112

   Each term is double the previous one, so 56 × 2 = 112.

6. Q6medium

   Find the next term in the series: 4, 9, 19, 39, 79, ?

   • A149
   • B159
   • C169
   • D158
   Show answer & solution

   Correct answer: (B) 159

   Each term follows the rule ×2 + 1, so 79 × 2 + 1 = 159.

7. Q7hard

   Find the next term in the series: 120, 99, 80, 63, 48, ?

   • A33
   • B34
   • C35
   • D37
   Show answer & solution

   Correct answer: (C) 35

   The differences are −21, −19, −17, −15, −13, so the next term is 48 − 13 = 35.

8. Q8medium

   Find the next term in the series: 2, 3, 5, 8, 13, 21, ?

   • A30
   • B32
   • C33
   • D34
   Show answer & solution

   Correct answer: (D) 34

   Each term is the sum of the two preceding terms, so 13 + 21 = 34.

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