Question

Find the number of arrangements of the word PARABOLA such that no 2 A's can be together.

Answer 1

you have to use method of gaps....
first arrange all the letters of the parabola except 3 A's

you can arrange 5 words in 5! ways
now you have to arrange 3A in 6 places... so u can do this in 6C3 ways....
final answer will be product of these two
= 120*{720/(6*6)}
20*120
2400 ways