In a class there are two sections A and B. If 10 students of section B shift over to section A, the strength of A becomes three times the strength of B. But if 10 students shift over from A to B, both A and B become equal in strength. How many students are there in sections A and B?
1. 50 and 30
2.45 and 15
3.90 and 40
4.80 and 40
Answer:1