How much of a perfume that sells for $35 dollars per ounce should be mixed with a perfume that sells for $15 per ounce to make a 3 oz bottle of perfume that can be sold for $63

Let x = ounces of $35 perfume

Let y = ounces of $15 perfume.

We want a 3-ounce perfume, therefore

x + y = 3

or

y = 3 - x (1)

We want the 3-ounce perfume to cost $63. Therefore

35x + 15y = 63 (2)

Substitute (1) in (2).

35x + 15 (3 - x) = 63

35x + 45 - 15x = 63

20x = 63 - 45 = 18

x = 18/20 = 0.9

From (1), obtain

y = 3 - 0.9 = 2.1

Answer:

0.9 ounces of $35 perfume and 2.1 ounces of $15 perfume.