plane 1 travels 395 miles in 1 hour
plane 2 travels 422 miles in 1 hour
together, they travel (395+422) 817 miles in 1 hour
to have 2451 miles between then, they'd need to travel
so in 3 hours, they'll be 2451 miles apart
So.. both sides divided by 4.
Now u have 14/68=x/6 -5
Multiply all by 6
Now u have 84/68=x-30
21/17+510/17=x
531/17=x
X=31 4/17
7-4=3
10-7=3
13-10=3
we can see that this is an arithmetic sequence with a difference of 3
the nth term=the first term +(n-1) times the difference
so a(n)=4+3(n-1)
One third of 27 is 9, which would mean you would just divide 9 over 48.