Ahmed sells fruits in his shop. One morning, he got 3 boxes of oranges from 3 different suppliers.

The label on the box he received from the first supplier says that it contains 60 oranges
with a total weight of 5400 g.

The label on the box he received from the second supplier says that it contains 20 oranges, and has a mean weight of 105 g for one orange.

Ahmed put all the oranges from the two boxes in one big container.

Find the mean weight of an orange in the big container.

When he received the box from the third supplier, he put all the oranges in the same big container. Therefore, the mean weight of an orange in the big container became 92.5.

Given that the label in the third box shows that the total weight is 3600 g, find the number of oranges in the third box.