Shnop D.

In the park, there were lindens and maples. Maples made up $60 \%$ of them. In the spring, lindens were planted in the park, after which maples accounted for $20 \%$. In the fall, maples were planted, and maples again made up $60 \%$. By what factor did the number of trees in the park increase over the year?
At first, there were 1.5 times fewer lindens than maples, and in the summer, there became 4 times more. At the same time, the number of maples did not change. Therefore, the number of lindens became $1.5 \cdot 4=6$ times more.

By the end of the year, the ratio of the number of lindens to the total number of trees became the same as it was at the beginning. But in the fall, the number of lindens did not change, so the total number of trees (compared to the initial) increased by six times.

## Answer

6 times.