algebra
posted by donny .
two planes take off from an airport at the same time and head in opposite directions at 260mph and 275mph respectively. in how many hours will they be 1605 miles apart?

distance covered by first plane  x miles
distance covered by second plane  1605x miles
time taken by first plane  x/260 hours
time taken by second plane  (1605x)/275
aren't those two times equal?
set the above times equal to each other and solve