A car leaves San Francisco for Los Angeles traveling an aver

A car leaves San Francisco for Los Angeles traveling an average of 60mph. At the same time, another car leaves LA for San Francisco traveling at 50mph. If it is 440miles between SanFrancisco and LA, howlong before the 2 cars meet, assuming that each maintains its average speed?

Solution

Distance(d)=rate(r) times time(t)or d=rt; t=d/r; r=d/t
Car A\'s average rate of speed=60mph
Car B\'s average rate of speed=50mph
When the distance car A has traveled plus the distance car B has traveled equals 440 mi, then the two cars are together.
Car A\'s distance=rt(car A)=60t
Car B\'s distance=rt(car B)=50t
So:
60t+50t=440
110t=440 divide both sides by 110
t=4 hours------------------elapsed time \'till the two cars meet.
CK
60*4+50*4=440
240+200=440
440=440