The actual price of the mixture
= 140*100/120 = 116.67/kg
Let x be price of the cheaper tea then the the costlier tea is worth 2x. Since the costlier tea is mixed with cheaper in the ratio 2:3.
2/5*(2x) + 3/5*(x) = 116.67
x = 83.33/kg
2x = 166.67.
Therefore the prices of each tea are 166.67/- & 83.33/-.