Solution:
When the bike moves with the wind, the wind increases its speed and the rate is r + 3
When the bike moves against the wind, the wind decreases its speed and the rate is r - 3
The time taken is given as:
[tex]Time\ taken = speed \times distance[/tex]
Link can ride his bike 20 miles into a 3 mph headwind and the same amount of time he can ride 30 miles with a 3 mph tailwind
Therefore,
[tex]20(r+3) = 30(r-3)\\\\20r + 60 = 30r - 90\\\\30r - 20r = 60+90\\\\10r = 150\\\\r = 15[/tex]
The speed of Link bike is 15 mph
