We have 7770 balls available, and there is 1 ball on d top of rack and then 3 balls on d 1st floor behind the top rack (horizontal rack) and then 6 balls on 2nd floor then 10 balls on 3rd floor,
How many floors can be accomdated with the given no of balls...???  Select
A) 36  B) 35  C) 34  D) 33  E) 32
1+3+6+10+........=7770 sum of triangular number   n*(n+1)*(n+2)/6 gives 35   ANSWER:35
<result>B</result>
We have 7770 balls available, and there is 1 ball on d top of rack and then 3 balls on d 1st floor behind the top rack (horizontal rack) and then 6 balls on 2nd floor then 10 balls on 3rd floor,
How many floors can be accomdated with the given no of balls...???