A.8 Even/Odd/middle positions

Questions

  1. POSTAGE: vowels at even positions
  2. ARTICLE: vowels at odd positions
  3. SECOND: Use 1 vowel and 2 consonants & vowel in middle. □ □ □
  4. Make 3-letters words from 7 consonants and 3 vowels so vowels are in middle.
  5. CAMBRIDGE: Use 5 letters including all vowels.
  6. EQUATION: 4-letters words keeping Q excluding N.

Answers

  • 3!4!
  • \(^4P_3 \times 4!=576\)
  • \(^2P_1 \times \space ^4P_2\)
  • \(^3P_1 \times \space ^7P_2=126\)
  • \(^5P_3 \times \space ^6P_2\)
  • \(^4P_1 \times \space ^6P_3\)