A shopkeeper mixed low-quality vegetable oil costing Rs. 40 per litre with sunflower refined oil costing Rs. 80 per litre in the ratio of 2 ∶ 3 respectively. If he sold the mixture at Rs. 100 per litre, find his profit percentage.
1
42.75%
2
47.5%
3
51.5%
4
56.25%