Question 329028
let the time they take when they  will be 80 miles apart be t
speed of one ship =16mph
it will travel 16t miles
..
speed of other ship = 12 mph
it will travel 12 t miles
..
they are at right angles
(12t)^2+(16t)^2=80^2
144t^2+256t^2=6400
400t^2=6400
t^2=6400/400
t^2=16
t=4 hours
after 4 hours they will be 80 miles apart