Answer: Option C
Answer: (c)
Let original price of rice per kg = Rs.x (let)
New price of rice per kg = Rs.${3x}/4$
$600/{{3x}/4} - 600/x = 10$
$600(4/{3x} - 1/x) = 10$
$600({4 - 3}/{3x})$ = 10
$600/{3x} = 10 ⇒ x = 600/30 = Rs.20$
New price = ${3x}/4 = {3 × 20}/4$ = Rs.15/kg
Method 2: Simple Approach,
If the price of an article is reduced by a% and buyer gets c kg more for some Rs.b, the new price per kg of article = ${ab}/{100 × c}$
= ${25 × 600}/{100 × 10}$ = Rs.15
Using Rule 31,
Reduced price per kg = ${25 × 600}/{100 × 10}$ = Rs.15