Multiple choice

A series is given with two terms missing, choose the correct alternative from the given ones that will complete the series. $87, 90, 84, 88, 81, ?, ?$

  1. $86, 78$
  2. $22, 36$
  3. $85, 93$
  4. $30, 45$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The series alternates between addition and subtraction: 87+3=90, 90-6=84, 88+4=88 (correction: 84+4=88), 88-7=81. Following this pattern: 81+5=86, then 86-8=78. The additions increase by 1 (3,4,5) and subtractions increase by 1 (6,7,8). Option A (86,78) correctly completes this alternating pattern.

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