In what ratio must tea at Rs. 62 per kg be mixed with tea at Rs. 72 per kg so that the mixture must. be worth Rs. 64.50 per kg?
Let the quantity of the tea that is Rs. 62 per kg be x kg and that of tea that is Rs. 72 per kg be y kg.
Hence, the required ratio is x:y.
Price of x kg tea =Rs. 62x
Price of y kg tea =Rs. 72y
If we mix both varieties of tea, the quantity of the mixture will be x+y.
Now, this mixture is Rs. 64.50 per kg.
Hence, the total price of mixture =Rs. 64.50(x+y)
So, 62x+72y=64.50(x+y)
⇒62x+72y=64.5x+64.5y
⇒64.5x−62x=72y−64.5y
⇒2.5x=7.5y
So, x:y=3:1
Hence, the required ratio is 3:1.