急需求助。。。。

hui_huang

谁可以帮我解道数学题啊。。。。非常感谢。。。。
There were some oval and circular shapes in a box. Durai put 48 more circular shapes in the box. Then 40% of the shapes in the box were oval shapes . Later, Durai put another 135 oval shapes in the box. 60% of the shapes in the box were oval shapes now. How many circular shapes were in the box at first?

jjrchome

更正：以上应为nos of circular shapes at first