Multiple choice

Find the wrong number in the following number series?(7, 3, 5, 7, 16, 42)

  1. $7$
  2. $5$
  3. $16$
  4. $42$
  5. $3$
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This follows a pattern where each term is obtained from the previous two: termₙ = termₙ₋₂ + 2×termₙ₋₁. Verifying: 7, 3, 5+2(3)=11 (not 7), 3+2(7)=17 (not 7), etc. The pattern fails at multiple points. However, examining positions: odd positions 7, 5, 16 (difference -2, +11) and even positions 3, 7, 42 (difference +4, +35). The number 3 at position 2 is the first number that disrupts what could have been a consistent alternating pattern if the sequence started differently.