Q. As a result of a 25% hike in the price of rice per kg, a person is able to purchase 6 kg less rice for Rs 1,200. What was the original price of rice per kg?

The correct option is B ₹ 40

$LettheoriginalpriceofRice/kg=₹R,andtheoriginalweightofricepurchased=Wkgs.$

$So,initiallyR\times W=1200.....Eqn\left(i\right)$

$Dueto25\%hikeinprice,newpriceofrice/kg=₹1.25R=\left(5/4\right)R,andnewweight=(W–6)kg$

$Now,\left(5/4\right)R\times (W–6)=1200,\to RW–6R=1200\times 4/5=960$
$\to fromeqn.\left(i\right),1200–6R=960or6R=1200–960=240.$
$\to R=240/6=₹40perkg.$