مسائل Math 2 جامدةhttp://www.thanwya.com/vb/images/smilies/049gc0.gif

[ahmedmath12]

I think thay 5 km/h sould be 5 m/min.
solution
s2=x2+3600
at x = 80 m/min
then s = 100 m/min
by talking the deritive of the both sides then
2s ds/dt=2x dx/dt
then
ds/dt=-4
thnks for all