SOLUTION: while driving home from school you travel at 100 km/h for 120 km then slow to 60 km/h you get home in 2 hours. 1: How far is you home town from school? 2: What is the average spe

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Question 1070353: while driving home from school you travel at 100 km/h for 120 km then slow to 60 km/h you get home in 2 hours.
1: How far is you home town from school?
2: What is the average speed?

Found 2 solutions by rothauserc, josmiceli:
Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
rate * time = distance
:
t(1) = 120 / 100 = 1.2 hours
:
t(2) = 2 - 1.2 = 0.8 hours
:
60 * 0.8 = 48 km
:
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total distance is 120 + 48 = 168 km
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:
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average speed = 168 / 2 = 84 km/hour
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:

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +d+ = distance in km traveled at +60+ km/hr
+120%2F100+%2B+d%2F60+=+2+
+6%2F5+%2B+d%2F60+=+2+
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(1)
Multiply both sides of the equation by +60+
+6%2A12+%2B+d+=+2%2A60+
+72+%2B+d+=+120+
+d+=+48+
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+120+%2B+48++=+168+ km
The home town is 168 km from school
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(2)
Average speed is always
[ total distance traveled ] / [ total time spent traveling ]
+168+%2F+2+=+84+
The average speed is 84 km/hr
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Check my math and get another opinion if necessary