AMC 12A 2004 Problem 4

Bertha has 6 daughters and no sons. Some of her daughters have 6 daughters, and the rest have none. Bertha has a total of 30 daughters and granddaughters, and no great-granddaughters. How many of Bertha’s daughters and granddaughters have no daughters?

Answer Choices
A. 22
B. 23
C. 24
D. 25
E. 26