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CAHSEE Math 3.1 Statistics, Data, and Probability II 170 Views
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Description:
Statistics, Data, and Probability II Drill 3 Problem 1. According to the graph, when do the cars achieve their greatest difference in speeds?
Transcript
- 00:02
Here's your shmoop du jour...
- 00:04
Two cars, starting at the same place, took different routes to the same destination.
- 00:09
Their speeds with respect to time are given by the graph shown below.
- 00:13
According to the graph, when do the cars achieve their greatest difference in speeds?
- 00:19
And here are the potential answers:
Full Transcript
- 00:24
Can we read a line graph?
- 00:26
The question is asking for a DIFFERENCE in speed so
- 00:30
we know there’s a big fat subtraction problem coming.
- 00:33
We just have to know what we’re subtracting from what.
- 00:37
And we’re on the hunt for the biggest difference here… so where are the lines furthest apart?
- 00:43
…let’s just use the potential answer set to figure out the differences.
- 00:47
A says: After 5 minutes.
- 00:49
Well, if this is after 20 minutes… and half way back to t minus zero is here – that’ll
- 00:55
be the 10 minute mark and half way again puts us here at the 5 minute mark…
- 01:00
So… ok… we put our ruler here and draw a line straight up…
- 01:06
…and we intersect the blue line at about the 15 mile per hour mark and then don’t
- 01:11
hit green line car 1 until the 40 minute mark.
- 01:15
A difference of 25 miles an hour. OK, how about B? After 10 minutes, blue is
- 01:21
at about 37 miles an hour and green is about 50 miles an hour… so just about 13 miles
- 01:28
an hour difference there. A is still winning. C. Well, after 20 minutes they are about the
- 01:34
same speed so C doesn’t have a prayer. Let’s try D. Green is about 62 and blue
- 01:41
is about 70 – slow and steady wins the race, we guess…
- 01:45
…but we didn’t care WHO wins – all we care about for this problem is at what point
- 01:49
there is the greatest distance between the two cars.
- 01:53
It looks like the winner is answer A with 25 miles an hour difference after minute 5.
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