Management Aptitude Test Dec 2019 Paper

(b) SP of 1 kg of mixture $=\mathit{₹}13,$ gain $=30\%$
$\therefore \mathrm{CP}$ of $1\mathrm{kg}$ of mixture $=\mathit{₹}\left(\frac{100}{130}\times 13\right)=\mathit{₹}10$
Let the cost of 2nd variety $=\mathit{₹}\mathit{x}$
Then, the cost of 1st variety $=\mathit{₹}\left(\mathit{x}+7\right)$
By the rule of alligation,
1st variety wheat $\mathit{₹}\left(\mathit{x}+7\right)$ 2nd variety wheat $\mathit{₹}\mathit{x}$ Now, $\frac{10-\mathit{x}}{\mathit{x}-3}=\frac{2}{5}$ $\Rightarrow 50-5\mathit{x}=2\mathit{x}-6$
$\Rightarrow 7\mathit{x}=56\Rightarrow \mathit{x}=8$
Thus, the cost of first variety $=\mathit{₹}\left(\mathit{x}+7\right)=\mathit{₹}\left(8+7\right)=\mathit{₹}15$