In what ratio must rice at ₹60 per kg is mixed with rice at ₹90 per kg so that the mixture be worth ₹80 per kg?

1:2

The correct answer is Option (4) → 1:2

Let the quantities of rice at ₹60/kg and ₹90/kg be mixed in the ratio $x:y$.

By allegation method:

Price of mixture = ₹80/kg

Difference with cheaper rice: $90 - 80 = 10$

Difference with expensive rice: $80 - 60 = 20$

Ratio of quantities: $x : y = 10 : 20 = 1 : 2$