Question

A chemist prepares 100 grams of medicine by mixing two ingredients X and Y. The rate of X is ₹1,500 per 100 grams and that of Y is ₹50 per 10 grams. X and Y are mixed in such a way that the cost of the resulting medicine is ₹13 per gram. What is the quantity of X (in grams) in the medicine ?

• A. 10
• B. 30
• C. 80
• D. 20

Answer 1

Answer:

C. 80

First convert all rates to ₹ per gram:

• Ingredient X: ₹1500 per 100 g ⇒ ₹15 per g

• Ingredient Y: ₹50 per 10 g ⇒ ₹5 per g

Let quantity of X = (x) grams
Then quantity of Y = (100 - x) grams

Use average cost

Total cost = (13 \times 100 = 1300)

$15x + 5(100 - x) = 1300$
$15x + 500 - 5x = 1300$
10x = 800

x = 80
Quantity of X = 80 grams