Using a chart:
At noon a private plane left Austin for Los Angeles,2100km away, flying at 500km/h. One hour later a jet left Los Angeles for Austin at 700km/h. At what time did they pass each other?
Private plane: 500km/h * 1h = 500km
Head-start.
d1 + d2 = 2100 km
500+500t + 700t = 2100
1200t = 2100-500 = 1600
t = 4/3 = 1 1/3 Hours(1:20 PM).
To find out at what time the two planes passed each other, we can create a chart or a table to track their positions and times.
Let's set up a chart:
Time (in hours) | Distance traveled by the private plane (in km) | Distance traveled by the jet (in km)
-----------------------------------------------|----------------------------------------------------|------------------------------------------------
12:00 PM | 0 | N/A (not started yet)
1:00 PM | 500 | 0
2:00 PM | 1000 | 700
3:00 PM | 1500 | 1400
... | ... | ...
At 12:00 PM, the private plane had not started yet, so its distance traveled is 0. The jet has not left Los Angeles yet, so its distance traveled is not applicable (N/A).
After one hour, at 1:00 PM, the private plane would have traveled 500 km. The jet, on the other hand, would have started from Los Angeles and has traveled 0 km.
As the planes pass each other when their total distance traveled is equal to the total distance between Austin and Los Angeles (2100 km), we can see that they pass each other when the sum of their distances traveled is equal to 2100 km.
Let's fill in the chart to determine when they passed each other:
Time (in hours) | Distance traveled by the private plane (in km) | Distance traveled by the jet (in km)
-----------------------------------------------|----------------------------------------------------|------------------------------------------------
12:00 PM | 0 | N/A (not started yet)
1:00 PM | 500 | 0
2:00 PM | 1000 | 700
3:00 PM | 1500 | 1400
4:00 PM | 2000 | 2100
From the chart, we can see that at 4:00 PM, the private plane has traveled a total of 2000 km, and the jet has traveled a total of 2100 km. At this point, they have passed each other.
Therefore, the private plane and the jet passed each other at 4:00 PM.