Question 863033
In 9 minutes, plane A travels {{{120/60}}}*9, or 2*9, or 18 miles [60 minutes in an hour; you're finding how fast it travels in one minute, so mph divided by minutes]
In 9 minutes, plane B travel {{{180/60}}}*9, or 3*9, or 27 miles
How many miles together?  (Because they are traveling away from each other, add)
18 + 27 = 45