The students in three batches of BBA are in the ratio 2 ∶ 3 ∶ 5. If 20 students are increased in each batch, the ratio changes to 4∶5∶7. The total number of students in the three batches taken together, before the increase, is ________.
1
10
2
90
3
100
4
More than one of the above
5
None of the above