Question

Gunpowder is made by mixing saltpetre and nitrous oxide. Price of saltpetre is thrice of price of nitrous oxide. Glen sells the gunpowder for $2160 per 10gm, thereby making a profit of 20%. If the ratio of saltpetre and nitrous oxide in the mixture is 2:3, find the cost of saltpetre.

Answer 1

the answer file is attached

Answer 2

The cost of each gram of saltpetre is $300

Step-by-step explanation:

Let the price of one gram of saltpeter is $3x and that of one gram of nitrous oxide is $x.

Now, in 10 gm of gun powder, the ratio of saltpeter and nitrous oxide is 2 : 3.

So, there are 4 gm of saltpeter and 6 gm of nitrous oxide in the mixture.

So, the cost price (C) of 10 gm of gun powder is $(4 × 3x + 6 × x) = $18x.

Now, given that Glen sells the gunpowder for $2160 per 10 gm, thereby making a profit of 20%.

So, we can write $C(1 + \frac{20}{100}) = 2160$

⇒ 1.2C = 2160

⇒ C = $1800.

Hence, we can write 18x = 1800

⇒ x = 100

So, the cost of each gram of saltpetre is $3x = $300 (Answer)