Answer:
River C is 2,860 miles
River D is 2,660 miles
Explanation:
Set up a system of equations with the information given.
River C is 200 miles than River D, so
C = D + 200
If the sum of both rivers is 5,520 miles, then
C + D = 5520
First plug in D + 200 for C in the second equation, to find River D’s length
D + 200 + D = 5520
2D + 200 = 5520
Subtract 200 on both sides
2D + 200 = 5520
-200 -200
2D = 5320
Divide by 2 on both sides
2D/2 = 5320/2
D = 2660 miles
To find River C’s length, plug D in the first equation.
C = D + 200
C = 2660 + 200
C = 2860 miles