Aptitude - Alligation or Mixture - Discussion

No the answer is correct ,though it does not use the standard alligation formula.

Reverse work the answer
2/5th of 1 kg of mixed rice = 0.4 kg of 1st variety @ Rs 7.2/Kg dearer ricee.
3/5th of 1 kg of mixed rice=0.6 kg of 2nd variety @ Rs 5.7/Kg cheaper rice.
Therefore the sum of cost price of individual component as per the ratio mixture must be equal to cost price of 1kg of the mixture
(7.2 * 0.4) + (0.6 * 5.7) = 6.3.

Also no option of 3:2.

I think the answer is correct.
2 parts of 720 + 3 parts of 570.
=> 2 * 720+3 * 570 = 3150.
Per kg rice(i.e.,mean price)= 3150/5 = 630.
{hear 5 is 2:3}
2:3 is correct instead 3:2.

No cheaper quantity is mixed in more amount so answer is 2 : 3.

How 630 came? Please explain me.

Thanks for the explanations.

How 90:30 come?

Correct, Thanks @Pushpa.

How 60 & 90 came here?

Thank you, your explanation was helpful.

Hello, According to alligation rule the answer is wrong. But I referred some books, I came to know that when in the question we gave the same kind of products like (first kind of rice and second of rice as given in the above question).
We should take the allegation rule as per question sequence.

In the above question, we have the highest value 7.20 first followed by 5.70. So we should take 7.20 first in alligation rule.

Hope my answer is helpful.