There are two varieties of rice. Variety 1 costs Rs. 100 per kg and variety 2 costs Rs. 120 per kg. The vendor mixed both the varieties and sold for 121 per kg and gained 10%. Find the ratio of variety 1 to variety 2 rice in the mixture.
1
1 ∶ 1
2
3 ∶ 1
3
2 ∶ 1
4
1 ∶ 3