Question 957485
Plane A in t time will go 312t (rate x time), plus 450
Then we have plane B, in t time it will go 385t. And we want to see them catch up, so we set our equation like this:
{{{385t= 312t+450}}} Subtract 312t from both sides:
{{{73t = 450}}} Now divide both sides by 73
t= 6.164 hours is how long it will take plane B to catch up with plane A.
Check: 
{{{312*6.164+450= 385*6.164}}}
{{{1923.168+450= 2373}}}
{{{2373=2373}}} Correct.