When counting the descendants, don't forget about the sons of Gvidon.

## Solution

Every descendant of King Gvidon is either a son of one of his descendants or a son of Gvidon himself. According to the condition, all the descendants of Gvidon had a total of 300 sons. And Gvidon himself had 5 sons, so the total number of descendants was 305.

## Answer

305.
$\left.\frac{[\text { Counting in two ways }]}{[\text { Trees }}\right]$

Tsar Guidon had 5 sons. Among his descendants, 100 each had exactly 3 sons, and the rest died childless.

How many descendants did Tsar Guidon have

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