cant figure out how to solve the problem

Question

Two boats leave port at the same time. One heading north at 35 knots, the other heading south at 47 knots.  How long will it take them to be 738 nautical moles apart ( one knot= one nautical mile per hour)

Answer 1

They leave the same origin and are traveling in opposite directions. So they are both on the same line, and the distance between them is just the sum of the distances each has traveled.

Let t be the time in hours.
Then 35 t + 47 t = 738.
so 82t = 738 so t = 9

They leave the same origin and are traveling in opposite directions. So they are both on the same line, and the distance between them is just the sum of the distances each has traveled.

 

Let t be the time in hours.

Then 35 t + 47 t = 738.

so 82t = 738 so t = 9