At Mumbai bus depot there are $1024$ buses. Every hour, half the buses depart for different destinations. After how many hours, does the depot have only one bus?

The municipal corporation authorities decided to plant trees on either side of a highway. The sum of all the numbers allotted to the trees was $1260$. Find the total number of trees on the highway if the first tree is numbered as $0, 2^{\mathrm{nd}}$ as $2$ and $3^{\mathrm{rd}}$ as $4$ and so on.