[ Arithmetic. Mental calculation, etc. ]  [ Problems on percentages and ratios ]

## Author: Klepcyn V.A.

Vanya had a certain number of cookies; he ate some, and then Tanya came to visit, and they divided the remaining cookies equally. It turned out that Vanya ate five times more cookies than Tanya. What fraction of all the cookies did Vanya eat by the time Tanya arrived?
Before Tanya arrived, Vanya ate four times more cookies than Tanya, which is twice as many as both of them ate after Tanya arrived.

## Answer

$2 / 3$.

直接输出翻译结果。