Answer:
Step-by-step explanation:
Let s represent the number of Senators in the Congress. Then the number of Representatives is (5s-20) and the total number of members is ...
s + (5s -20) = 520
6s = 540 . . . . . . . . . add 20, simplify
s = 90 . . . . . . . . . . . divide by 6
The number of Senators is 90; the number of Representatives is 430.
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You can find the number of Representatives either as 520 -90 = 430 or as 5·90 -20 = 430.