Answer:
15 ounces of red beans
Step-by-step explanation:
So, we know Kim's soup contains a total of 75 ounces of beans, including red beans (r) and black beans (b), so r + b = 75
Then we know that for each ounce of red beans, there are 4 ounces of black beans, 1b = 4r
Then we merge both equations by replacing b's value in the first equation by its equivalent (b = 4r), since we are looking for the count of red beans.
r + b = 75
r + 4r = 75
5 r = 75
r = 15
There are 15 ounces of red beans in Kim's soup, that looks a lot like the last chili I made :-)