<p>Cars are either white or black. The ratio of white cars to black cars is 2/3. There could be the following number of cars EXCEPT: a) 10 b)12 c)15 d)30 e)60 I say (a) because 10 is not divisible by 3. book says 12???</p>
<p>This one i am less sure about...</p>
<p>If m is the greatest prime factor of 38 and n is the greatest prime factor of 100 what is m+n ? a)7 b)12 c)24 d)29 e)44</p>
<p>Again I say (a) because of 38/2 and 100/5 5+2 = 7. books says 24. Am i missing a factor of a hundred??? or is it wrong again?</p>
<p>And finally...</p>
<p>5 cards are placed in a row so that one card in particular is never at either end. How many different combinations are possible.</p>
<p>I say 4<em>4</em>3<em>1</em>1 because you can only pick 4 that arent the bad card first and then are left to pick any the 2nd and 3rd time. However the 4th time you must pick the card isnt bad so you can only pick one instead of either of the two and you must pick a good card of which you only have 1 last.</p>
<p>I say 48. Book says 72. This one i am completely unsure about.</p>
<p>Thnks - Sock :)</p>
<p>"Cars are either white or black. The ratio of white cars to black cars is 2/3. There could be the following number of cars EXCEPT: a) 10 b)12 c)15 d)30 e)60"</p>
<p>The answer is 12 because it is the only number not divisible by 5. Notice, the ratio of white/black cars is 2/3. That means there are 2 PARTS white cars to 3 PARTS black cars. So how many TOTAL PARTS are there? 2+3, 5 parts. Therefore the number of cars must be a multiple of 5, which 12 is not.</p>
<p>"If m is the greatest prime factor of 38 and n is the greatest prime factor of 100 what is m+n ?"</p>
<p>I think you just made an arithmetic mistake on this one, because you described the right answer, but got the wrong number. 38/2 = 19 + 5 = 24. </p>
<p>The last one about the cards has been answered many times before and should be on the consolidated list of solutions. Basically the idea is you ask yourself at each step "How many cards can I draw from?" and just multiply those numbers together. Don't think about it too hard - just follow the instructions precisely and you'll get 72.</p>
<p>Feel free to post more questions if you have them.</p>
<p>Andre</p>
<p>For the cards problem: fill the slots in the order 1-5-2-3-4. The #possibilities is 4<em>3</em>3<em>2</em>1 = 72 .</p>