If 15 apples cost as muchas 6 strawberries, 2 strawberries cost as much as 16 bananas, 6 bananas cost as much as 15 potatoes, then whatis the cost of 1 potato if an apple costs ₹ 20?

15A = 6S => A : S = 6 : 15
2S = 16B => S : B = 16 : 2
6B = 15P => B : P = 15 : 6
where A = Apples, S = Straw berries, B = Bananas and P = Potatoes
Multiplying A : S by 16 and S : B by 15,
A : S = 96 : 240 and S : B = 240 : 30
Hence, A : S : B = 96 : 240 : 30
Multiplying B : P by 2,
B : P = 30 : 12
Then, A : S : B : P = 96 : 240 : 30 : 12
Let the cost of Apples, Straw berries, Bananas and Potatoes be Rs.96x, Rs,240x, Rs.30x and Rs.12x respectively.
Given, Rs.96x = 20 => x = $$\dfrac{20}{96} = \dfrac{5}{24}$$
Therefore, Cost of 1 potato =  12x = $$12\times \dfrac{5}{24} = Rs.2.5$$