<p>hi,
I've been working through barron's math workbook, and I came across this problem, and I can't find a way to solve it. can anyone help me with it??
This is the problem:
In a school election, Susan received 2/3 of the ballot cast, Mary received 1/5 of the remaining ballots, and Bill received all of the other votes. If Bill received 48 votes, how many votes did Susan receive?
a. 75
b. 90
c. 120
d. 150
e. 180</p>
<p>Thanks!</p>
<p>Susan = 2/3
Mary = 1/5 x 1/3 (the remaining ballots) = 1/15
Bill = 1 - 2/3 - 1/15 = 4/15 </p>
<p>So if Bill got 48, then 4/15 of the total votes = 48
4/15x = 48
x = 180</p>
<p>Since Susan received 2/3 of the total votes, 2/3 x 180 = 120. That's the answer - (E).</p>
<p>^ Your answer is right, but the letter you chose for it is wrong. It's actually (C).</p>
<p>^^^ good observation <em>gives rockermcr cookie</em></p>
<p>lolol :)
FYI dont do that on the SAT jellybeanz.</p>
<p>Ahh math, the one subject that only has 1 possible answer.</p>
<p>thank you guys so much!</p>
<p>Thanks for the cookie, but, for future reference, I prefer cake :p</p>
<p>For this particular class of questions you can use a different approach.</p>
<p>Choose some good number for the total number of ballots, say, 30.
Susan then received (2/3)30 = 20 ballots,
Mary (1/5)10 = 2, and there are 8 left for Bill.
Since Bill should get 48, to obtain the correct numbers we should multiply ours by 6, because 6x8 = 48.
We had 20 votes for Susan, so the correct answer will be 6x20 = 120.</p>
<p>Any cookies left? :)</p>
<p>i like your solution</p>
<p>thanks gcf101, here's a cookie. lol.</p>
<p>ok so how about this problem...
A soccer team has played 25 games and has won 60% of the games it has played. What is the minimum number of additional games the team must win in order to finish the season winning 80% of the games it has played?
a.28
b.25
c.21
d.18
e.15</p>
<p>25(.6) = 15 games won
(15+x)/(25+x)=0.8
15+x=20+.8x
.2x=5
x=25 >> (b). i hope i did the math correctly, becuz i did it in my head</p>
<p>Your answer is right, but I don't understand your calculations.</p>
<p>Edit: Nevermind.</p>
<p>40% lost games: (.4)25 = 10.
These 10 losses will be 20% at the end of a season (all other games have to be won).
100% will be 50 games then, and 50 - 25 = 25 additional games will be played.</p>
<p>Thanks, jellybeanz, for the cookie! I am crunching now on the remaining 50% of it. ;)</p>
<p>^ How did you know the 10 losses would be 20% at the end of the season? I don't see how you could tell just by knowing that the team won the rest of its games. I also don't understand how you came up with the 100% and 50 games figures, that you presented near the end of your post. Could you elaborate a little more please?</p>
<p>pretty simple. he noticed that the number of losses wouldnt change and that would be 20%, since the team's adding some wins to their stats to gain 80%.
so 10 - 20%
x - 100% -> x=50 (number of games that will have been played when they get 80:20 stat) then to find the number of games additionally played subtract 25 from 50. it's 25 then.</p>
<p>gcf101, i see you are great on maths. and i was just wondering if you ever got stumped on any math prob? if so, would you please give us that prob?</p>
<p>Oh alright I understand that approach now.</p>
<p>Thanks for the compliment, Tsenguun.</p>
<p>My explanation is probably a better fit for PM, but I'd like to answer your question here in case somebody asks it again.</p>
<p>I have to be proficient - I am a tutor.
I have also participated in math competitions, as well as coached for them.<br>
Heuristics is one of my strongest interests.</p>
<p>Of course, I've stumped on math problems, but not on the standardized tests.
I don't always find the best solution right on the test though.
Careless mistakes - that's what kills me on those tests. :mad:<br>
And to think that I teach how to avoid them! :eek:<br>
Need more practice. :o
Well, some of the math problems on Math 2 did stump me, but I always had enough time to tackle them, because I went fast enough through the rest of the questions.
I have not kept those hard questions: the last time I took SAT II was in June of 2006, plus I have never had students who strived to reach 800 on SAT II. Sorry! :o</p>