In what ratio must tea leaves costing ₹53 per kg be mixed with tea leaves costing ₹78 per kg, so that the mixture is worth ₹63 per kg?

💡 Solution & Explanation

Use alligation: the cheaper part : the dearer part = (dearer price − mixture price) : (mixture price − cheaper price) = (78 − 63) : (63 − 53) = 15 : 10, which simplifies to 3 : 2. Check: mixing in that ratio gives an average of ₹63 per kg. Writing the differences the other way round is the most common mistake.