In what ratio, should rice at ₹60 per kg be mixed with rice at ₹42 per kg such that by selling the mixture at ₹56 per kg there is a gain of 12%?

As per the question, the final selling price of the mixture should be ₹56 per kg to gain of 12%.

So if 100% is equal to the cost price of the final mixture.

Then (100+12)% = 56

112% = 56

$$1\%\ =\ \frac{56}{112}$$

$$100\%\ =\ \frac{56}{112}\times\ 100$$

the cost price of the final mixture = ₹50 per kg

Now we can apply the concept of mixture and alligation to get the required ratio in which both were mixed.

So the required ratio = 8 : 10

= 4:5