According to the condition, 1 pound of brass contains pounds of copper.
It is what the problem says, expressed in other words.
Then "m" lbs of brass contain (plural) pounds of copper. ANSWER
Solved, with explanations.
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comment from student : How did you obtain lbs. ?
My response : As the problem says, one pound of brass is (r + s) equal masses, where "r" is the number of parts of copper.
It IMMEDIATELY means that 1 pound of brass contains pounds of copper.
