Two ships leaving the same marina at the same time are 3.2 miles apart after sailing 2.5 hours. If they continue at the same rate and direction, how far apart will they be 2 hours later?

1 Answer
May 25, 2018

The two ships will be 5.76 miles apart from each other.

Explanation:

We can figure out the relative velocities of the two ships based on their distances after 2.5 hours:

#(V_2-V_1)xx2.5=3.2#

The above expression gives us a displacement between the two ships as a function of the difference in their initial velocities.

#(V_2-V_1)=3.2/2.5=32/25 mph#

Now that we know the relative velocity, we can figure out what the displacement is after the total time of 2.5+2=4.5 hours:

#(V_2-V_1)xx4.5=x#

#32/25xx4.5=x#

#32/25xx9/2=x#

#288/50=x#

#x=576/100=color(green)(5.76mi)#

We can confirm this by only doing the 2 hour delta, and adding it to the original displacement of 3.2 miles:

#32/25xx2=64/25=2.56mi#

#2.56+3.2=color(green)(5.76mi)#