(b) SP of 1 kg of mixture =₹13, gain =30% ∴CP of 1‌kg of mixture =₹(
100
130
×13)=₹10 Let the cost of 2nd variety =₹x Then, the cost of 1st variety =₹(x+7) By the rule of alligation, 1st variety wheat ₹(x+7) 2nd variety wheat ₹x
Now,
10−x
x−3
=
2
5
⇒50−5x=2x−6 ⇒7x=56⇒x=8 Thus, the cost of first variety =₹(x+7)=₹(8+7)=₹15