A small plane leaves an airport at a speed of 252 miles per hour. A jet leaves the airport 2 hours later traveling at 672 miles per hour. How long will the small plane be flying before the jet catches up to it

S=252t, j=672 (t-2), when the jet catches the small plane j=s so:

672 (t-2) = 252t

672t-1344=252t subtract 252t from both sides

420t-1344=0 add 1344 to both sides

420t=1344 divide both sides by 420

t=3.2 hours (3:12)

It will be approximately 2/3 of an hour, or about 40 minutes before the jet catches up to the plane