We will solve as follows:
First: We will use the i, j, k vector notation to describe each point as a vector:
[tex]A=4i-j+7k[/tex][tex]B=16i-10j+10k[/tex]Now, we have that the time it takes to get from A to B is 3 hours (t1). And the time it takes from B to C is 1 hour (t2).
Second: We determine the speed from A to B:
[tex]v=\frac{B-A}{t_1}\Rightarrow v=\frac{(16-4)i+(-10+1)j+(10-7)k}{3}[/tex][tex]\Rightarrow v=\frac{12i-9j+3k}{3}\Rightarrow v=4i-3j+k[/tex]Third: We now determine the value of C:
[tex]C=B+vt_2\Rightarrow C=(16+4)i+(-10-3)j+(10+1)k[/tex][tex]\Rightarrow C=20i-13j+11k[/tex]So, we would have that the coordinates of C are:
[tex]C=(20,-13,11)[/tex]