<p>Of the 240 campers at a summer camp, 5/6 could swim. If 1/3 of the campers took climbing lessons, what was the least possible number of campers taking climbing lessons who could swim?</p>
<p>A) 20
B) 40
C) 80
D) 120
E) 200</p>
<p>The answer was 40</p>
<p>ok so my usual way to solve a question is to mentally count the question writers and objects/people in the question in a negative way.</p>
<p>There are 240 idiots at this so called camp.</p>
<p>dont get scared of fractions!</p>
<p>They say 5/6 of them could swim in other words, 200 of them can swim!</p>
<p>They say 1/3 of them took climbing lessons. That means at LEAST 80 of them took climbing lessons. So go ahead and eliminate D,E.</p>
<p>SO now we can pick from 20,40, and 80.</p>
<p>Now the question states "least", and we know that only 40 people cannot swim. So A is already out of the picture, now that leaves us with 40,80. They asked for LEAST. 80-40 = 40.</p>
<p>B is your answer.</p>
<p>To minimize the number of swimbers (those who both swim and climb) no child should be left behind: each camper has to either swim, or climb, or both.
Based on the Venn diagramm:
Swimmers + Climbers - Swimbers = 240
200+80-x = 240
x = 40</p>
<p>swimmers = 5/6 . 240 = 200
climbers = 1/3 . 240 = 80
And now use the Euler circles to find out the answer
we have 40 campers who can't swim. And the problem is to find the least possible number of kids who can both swim and climb. So The minimum is when these 40 kids can only climb so the least number of campers who can both swim and climb is 80-40 = 40.</p>
<p>thanks!
10 chars</p>
<p>OK, I understand that because there are at most 80 climbers, D and E can be eliminated. I don't understand the logic from there on. </p>
<p>It seems that all these responses assume that everyone participates in at least one activity. How does that minimize the number who do both? It seems that if some campers did neither, that would detract from both those who swim and climb and hence those who do both. On the other hand, having campers who did neither would minimize those who only swim and who only climb, detracting from those who do both. I'm confused.</p>
<p>If everyone does one or more activity, I understand gcf's and Boyan's responses. I don't understand Scorpious' logic after D and E are eliminated. Can someone clarify?</p>
<p>Well, the easiest way to solve this problem is with a venn diagram.
But if I want to solve it with reasoning this is how I would explain it:</p>
<p>We have 200 campers who can swim and therefore 40 who can't. Out of all the campers 80 can climb. We assume that out of these 80 that can climb there are also some that can't and can swim. But the question asks for the least that can swim and climb, so we subtract 40(those who can't swim) from 80... and there you have it.</p>
<p>This is the way I understand it... hope it helps:)</p>
<p>im dommed!!</p>
<p>I know this has been answered, but here's a very simplified way to look at it.</p>
<p>They asked for the least number of rock climbers who can swim. Which means they want the most number of rock climbers who can't swim. 40 campers can't swim, 80 campers take climbing lessons. Since they're looking for the least number, **just pretend that all campers who can't swim take climbing lessons<a href="remember,%20they're%20asking%20for%20the%20least">/B</a>. Therefore, the answer is 40.</p>
<p>NOt so difficult but when you have 2 questions like this and have only 2 minutes left ... pff ;}</p>