Because it passed four times, there are four more people.

So [(4-1) 5+(4-1) * (-1) 5]/4 = 60.

The specific formula is as follows

[(r- 1)^(n+ 1)+(r- 1)*(- 1)^(n+ 1)]/r

How many people does r stand for

N represents how many times you have worn it.