ATAR Notes: Forum
VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: Special At Specialist on March 29, 2012, 10:50:45 pm
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The temperature T of a pot at time t is given by T = 100*(0.75)^(t/15).
Find the temperature of the pot after 30 minutes to the nearest tenth of a degree.
I substituted t = 30 to get:
T = 100*(0.75)^(2)
T = 56.25
Now I have to round it to either 56.3 or 56.2.
Do I round up or down???
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Up, in this case
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But the word "after" makes me think I would round down... it didn't say "at t = 30", it said "after 30 minutes".
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Its quite ambiguous and I'm not sure why the school would do something so trivial, but my reasoning is that at t=30, the temperature is above 56.2. In addition, the question asks for "after" t=30 (dodgy wording), so I think 56.3 will suffice :)
Ask your teacher just in case though
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It was on a SAC that I just did at school... I rounded it down but everyone else in the class rounded up, so I'm kind of worried. I wrote a sentence explaining why I rounded down so hopefully he marks both as correct because it was kind of ambiguous.
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I don't think its ambiguous, I would definitely round up. I'm going to assume that the little introduction said something like "... blah blah blah where t is the time in minutes AFTER some random event..."
so then to say 20 minutes AFTER would mean t is exactly 20... thats my interpretation..
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Oh well, it's better to lose a mark in a SAC than it is in the exam. This way, I can still get a 50.
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It was on a SAC that I just did at school... I rounded it down but everyone else in the class rounded up, so I'm kind of worried. I wrote a sentence explaining why I rounded down so hopefully he marks both as correct because it was kind of ambiguous.
It's a bad question.
You should never get asked questions where you have to make decisions like this.
It would never happen in a VCAA exam.
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It was on a SAC that I just did at school... I rounded it down but everyone else in the class rounded up, so I'm kind of worried. I wrote a sentence explaining why I rounded down so hopefully he marks both as correct because it was kind of ambiguous.
It's a bad question.
You should never get asked questions where you have to make decisions like this.
It would never happen in a VCAA exam.
For over 7 months, I believed you. Then I encountered question 4c on the 2012 tech-free methods exam which was just as ambiguous as this.