could there be an error from the CollegeBoard?

<p>Okay. I am probably out of line here but there is this math problem that i really don't agree with, is it me or something else.</p>

<p>so it says:</p>

<p>The daytime telephone rate between two cities is 90 cents for the first 3 minutes and c cents for each additional minute.The total charge is reduced 65 percent on calls made after 11:00 P.M the cost, in dollars, of a 30- minute call made at 11:15 P.M between the two cities.
(A) 0.35(0.90) + 27c
(B) 0.35(0.90+0.27c)
(C) 0.35(0.90+9c)
(D) 0.65(0.90+0.30c)
(E) 0.65(0.90+0.30c)</p>

<p>the collegeboard says the correct answer is B, but was there a typo here or sth because I really think that instead of 0.27c it should be 27c.</p>

<p>thanks to everyone who taps back</p>

<p>I believe because the question is asking for the cost of the call in dollars ($), .27C is used to convert cents to dollars.</p>

<p>For example, if you answered the question your way and it cost 25¢ a minute, then you would actually pay $675 for those 27 minutes instead of $6.75 because the units weren’t properly converted to dollars.</p>

<p>I hope that helps to clear things up for you, and watch out for those little tricks they throw in like that.</p>

<p>Why did it change to .35 instead of .65?</p>

<p>It’s deduced by 65%. So after 11:00pm the calls only cost 35% of what they are normally</p>

<p>^I don’t really understand, If it is reduced by 65% after 11 then why is 35%?</p>

<p>Because it said reduced BY 65%, not reduced TO 65%!</p>

<p>Say you start with $100. If we reduce that sum by, say 20%, then you need to find 20% of $100 which is $20. But that is the amount of the REDUCTION. Reduce $100 by $20 and you are left with $80.</p>

<p>Same thing in this problem: You would multiply by .65 to find 65%, but then when you take that away, you would be left with 35% or .35 times your original amount.</p>

<p>One more thing: since this gave you some trouble, you should consider using made up numbers: pick a value for c, work out the answer and then put that made up value into each answer choice. Seriously, this question is practically designed for that method!</p>

<p>Thanks got it now^</p>

<p>thanks brostradamus and pckeller.</p>

<p>i understand now. i kept plugging in c as 0.07 cents…but I just realized that they said c cents</p>