Problem solver. Need help plz

Question

Andrew rowed 20 miles downstream in 2.5hrs . the trip back however took him 4hrs. Find tbe rate that andrew rows in still water and the rate of the current. Express your answer as intergers or rounded to one decimal place?

Answer 1

20 = 2.5( r+s) = 2.5r + 2.5s

200 = 25r + 25s

20 = 4(r-s) = 4r - 4s

solves by elimination:

multiplies top equation by 4 and bottom equation by 25

800 = 100r + 100s

500 = 100r - 100s

1300 = 200r

r = 6.5

20 = 2.5*(6.5 + s)

20 = 16.25 + 2.5s

3.75 = 2.5 s

s= 3.75/2.5 = 1.5

Speed of the boat is 6.5.

Speed of the current is 1.5