a small island has 2/5 of its surface covered by forest and 1/4 of the remainder of its surface by sand dunes.The island
问题描述：
a small island has 2/5 of its surface covered by forest and 1/4 of the remainder of its surface by sand dunes.The island also has 90 hectares covered by farm land if the lsland is made up of only forest.what is the total area of the island.
答
题楼上已翻译题目的意思我就直接解了.如果不要方程的话：森林+沙丘：2/5+1/4=13/20那么剩下的就是农场：单位“1”-13/20=7/2090公顷=“7/20”:90÷7/20=1800/7公顷（好怪哦、、)=257又1/7公顷答：the total area od ...