posted by Michelle .
A row of seats in a stadium has 100 seats. If 12 people sit in a row so that there are 2 empty seats between any person and the next person, how many empty seats in the rpw are not between the two end people?
If there are four seats per row, one person sits at each end, and two spaces will be between them. The same goes for 7 seats, namely the first, fourth, and seventh will be occupied. Continuing this way, we know that seats will be occupied on the
1st, 7th, 10th, 13th, .... (3n+1)th.
So which is the occupied seat below or equal to the 100th seat?