Question

The school band is scheduled to march in the annual parade, but the band’s starting point is changed the day before the parade. The band director calls three band members. Each band member calls three other band members. Then these band members each call three members. How many band members, including the band director, are notified of the new starting point?

Answer 1

1+3+27+81.....
since its 3 times more

The sum of a geometric sequence is a(1-r^n)/(1-r)
where n is the number of calls, a is the starting point, and r is the ratio