Answer:
The length of river D is 2550
length of river C is 2550+500=3050
Explanation:
Let the river D be 'x'
and the river C is (x+500)
x + x + 500 = 5600
2x + 500 = 5600
2x = 5600 - 500
2x = 5100
x = 5100/2
x = 2550
The length of river D is 2550
length of river C is 2550+500=3050