Multiple choice

The number of different ways in which five 'alike dashes' and eight 'alike dots' can be arranged using only seven of these 'dashes' and 'dots' is

  1. $350$
  2. $120$
  3. $1287$

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We need to choose 7 items from 5 dashes and 8 dots. This is equivalent to finding the number of combinations of dashes (d) and dots (t) such that d + t = 7, where 0 <= d <= 5 and 0 <= t <= 8. Summing the combinations for each valid (d, t) pair gives the total arrangements.

Keep practicing — related questions