1) 60/(20+t)
2) 60/(20-t)
3) 60/(20-t) - 60/(20+t) = 120t/400-t²
4) 60/(20-t) : 60/(20+t) = (20+t)/(20-t)
1) 60/(20+t)
2) 60/(20-t)
3) 60/(20-t) - 60/(20+t) = 120t/400-t²
4) 60/(20-t) : 60/(20+t) = (20+t)/(20-t)