Question content area top Part 1 In a certain​ chemical, the ratio of zinc to copper is 4 to 15. A jar of the chemical contains 450 grams of copper. How many grams of zinc does it​ contain?

Answer 1

If the ratio of zinc to copper is 4 to 15, then there are infinite possibilities for the actual grams.

For example: 8 to 30, 12 to 45, 1 to 7.5. In other words there is some constant that can be multiplied times the 4 and 15 to determine the actual grams. Let k be that constant. Then the number of grams of zinc can be represented by 4k. The number of grams of copper can be represented by 15k. Note the 4k/15k reduces to 4/15,

We know the total number of grams in the chemical contains 450 grams. That means we can write:

4k + 15k = 450

19k = 450

k = 450/19 (constant of proportionality)

Since the number of grams of zinc is 4k, the actual number is 4(450/19) = 1800/19 or about 95 grams.

Note:

4(450/19) + 15(450/19) = 1800/19 + 6750/19 = 8550/19 = 450 (check)

Also, 1800/6750 = 4/15