Answer:
[tex]t = k \frac{1}{s} \\ 2 = k. \frac{1}{60} \\ k = 120 \\ k \: \: is \: constant \: of \: variation \\ relationship \: is \\ t = \frac{120}{s} . \\ when \: s \: = 90 \\ t = \frac{120}{90} \\ t = \frac{4}{3} \\ when \: t = 2 \frac{1}{2} \\ s = \frac{120}{2 \frac{1}{2} } \\ s = 48[/tex]
