SOLUTION: Car A starts in Sacramento at 11am. It travels along a 400 mile route to Los Angeles at 60 mph. Car B starts from Los Angeles at noon and travels to Sacramento along the same route

Algebra ->  Equations -> SOLUTION: Car A starts in Sacramento at 11am. It travels along a 400 mile route to Los Angeles at 60 mph. Car B starts from Los Angeles at noon and travels to Sacramento along the same route      Log On


   



Question 1209421: Car A starts in Sacramento at 11am. It travels along a 400 mile route to Los Angeles at 60 mph. Car B starts from Los Angeles at noon and travels to Sacramento along the same route at 75 mph. The route goes past Fresno which is 150 miles along the route from Los Angeles. How far from Fresno are the cars when they meet?
Found 3 solutions by ikleyn, mccravyedwin, greenestamps:
Answer by ikleyn(52800) About Me  (Show Source):
You can put this solution on YOUR website!
.
Car A starts in Sacramento at 11am. It travels along a 400 mile route to Los Angeles at 60 mph.
Car B starts from Los Angeles at noon and travels to Sacramento along the same route at 75 mph.
The route goes past Fresno which is 150 miles along the route from Los Angeles.
How far from Fresno are the cars when they meet?
~~~~~~~~~~~~~~~~~~~~~~~~~~

Let "t" be the time (in hours) for car A moving from S to LA to get the meeting moment.

Then the time for car B moving from LA to S is (t-1) hours to get the meeting point (one hour less).


The time equation for the meeting moment t is

    60t + 75*(t-1) = 400  miles  (the whole route length).


Simplify and find t from this equation

    60t + 75t - 75 = 400

    60t + 75t = 400 + 75

       135t   =    475

          t   =    475/135 = 3.518519  hours.


So, the time for the car B moving from LA to the meeting point is one hour less than that, i.e. 2.518519 hours.


The distance from LA to the meeting point is  75*2.518519 = 188.888925 miles.


It is 188.888925 -150 miles = 38.888925 miles from Fresno, between Fresno and Sacramento.


ANSWER.  The meeting point is 38.9 miles from Fresno, between Fresno and Sacramento.

Solved.



Answer by mccravyedwin(407) About Me  (Show Source):
You can put this solution on YOUR website!
   
Car A starts in Sacramento at 11am. It travels along a 400 mile route to Los Angeles at 60 mph.
Car B starts from Los Angeles at noon... 
So Car A is already 
d+%22%22=%22%22+rt+%22%22=%22%22+%2860%29%281%29+%22%22=%22%22+60 
miles toward Los Angeles when car B starts.
So at noon, when car B starts, they are 
400-60%22%22=%22%22340 
miles apart.
Car B starts from Los Angeles and travels to Sacramento along the same route at 75 mph.
So their approach rate is 
60%2B75%22%22=%22%22135
mph, so their 340 miles of separation will shrink to 0, i.e., they will meet in 
t%22%22=%22%22d%2Fr+%22%22=%22%22+340%2F135+%22%22=%22%22+68%2F27+%22%22=%22%22+2%2614%2F27 
hours after noon and when car B is 
d%22%22=%22%22rt+%22%22=%22%22+75%2868%2F27%29%22%22=%22%221700%2F9%22%22=%22%22188%268%2F9
miles from Los Angeles.
The route goes past Fresno which is 150 miles along the route from 
Los Angeles. How far from Fresno are the cars when they meet?
So they are 150 miles closer to Fresno than they are to Los Angeles by 
188%268%2F9  
miles. So the answer is 
188%268%2F9+-+150+%22%22=%22%22+38%268%2F9 miles from Fresno.

Edwin

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Between 11am and noon, car A travels 60 miles (1 hour at 60mph). So at noon, when car B starts traveling, the two cars are 400-60 = 340 miles apart.

The ratio of the speeds of the two cars is 60:75 = 4:5, so when the cars meet car A has traveled 4/9 of the remaining 340 miles and car B has traveled 5/9 of that distance.

So the distance from Los Angeles that car B is when the cars meet is 5/9 of 340 miles.

(5/9)340 = 1700/9

Car B is 1700/9 miles from Los Angeles when the cars meet, and Fresno is 150 miles from Los Angeles. The distance from Fresno when the cars meet is then

1700/9 - 150 = 1700/9 - 1350/9 = 350/9 = 38 8/9 miles or about 38.9 miles.

ANSWER: The two cars are (about) 38.9 miles north of Fresno when the cars meet.