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2004 AMC 10A Problem 6

Problem 6 of 25EasierCounting & Probability

Bertha has 66 daughters and no sons. Some of her daughters have 66 daughters, and the rest have none. Bertha has a total of 3030 daughters and granddaughters, and no great-granddaughters. How many of Bertha’s daughters and granddaughters have no daughters?

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Solution

Bertha has 306=2430 - 6 = 24 granddaughters, none of whom have daughters. These granddaughters belong to 246=4\frac{24}{6} = 4 of Bertha’s daughters. So exactly 44 women have daughters, and the number with no daughters is 304=26. 30 - 4 = 26. Thus, the correct answer is E.

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Concepts: basic counting · logical deduction

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