Answer:22 min
Step-by-step explanation:
we need to find the closest distance between two ship.
let us take the ships meet after time t
now distance travel by first ship at any time t is given by 20t
the position of second ship is 15-15t
let us take distance between them is d
therefore
[tex] D^2=\left ( 20t\right )^2+\left ( 15-15t\right )^2[/tex]
now to get the shortest distance differentiate D w.r.t time
[tex]D^2=625t^2-450t+225[/tex]
[tex]\frac{\mathrm{d}D }{\mathrm{d} t}=1250t-450=0[/tex]
t=0.36hr
thus at [tex]t=0.36hr \approx 21.6min\approx 22 min[/tex]
