Teas worth Rs. 126 per kg and Rs. 135 per kg are mixed with a third variety in the ratio 1 : 1 : 2. If the mixture is worth Rs 156 per Kg , the price of the third variety per Kg will be?
Choose the correct choice from the following answers:
A) rs . 147.50 B) rs . 785.50 C) rs . 178.50 D) rs . 258.50 E) none of these

Rationale: "explanation : since first and second varieties are mixed in equal proportions . so , their average price = rs . ( 126 + 135 ) / 2 . = > rs . 130.50 . so , the mixture is formed by mixing two varieties , one at rs . 130.50 per kg and the other at say , rs . x per kg in the ratio 2 : 2 , i . e . , 1 : 1 . we have to find x . by the rule of alligation , we have : cost of 1 kg cost of 1 kg of 1 st kind of 2 nd kind ( rs . 130.50 ) ( rs . x ) \ / mean price ( rs . 156 ) / \ x â ˆ ’ 156 22.50 = > x â ˆ ’ ( 156 / 22.50 ) = 1 . = > x â ˆ ’ 156 = 22.50 . = > x = 178.50 rs . answer : c"
Answer: C