Probability Help

Test Preparation SAT Preparation
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<p>Ugh probability questions, mostly involving combinations of principles/ combinations and permutations are not my forte. does anyone know any sites that can help?</p>

<p>also, can someone help me w/ this problem:</p>

<p>There are 3 roads from Plattsville to Ocean Heights and 4 from Plattsville to Bay Cove. If Martina drives from Plattsville to Bay Cove and back and passes through OCeans Heights each time, how many possible routes are there?</p>

<p>I drew a diagram, and got 3 * 4 * 3 (3 to O and 4 to P and then back there are 3 routes again)= 36), but the answer is 72 :/</p>

<p>Thanks :)</p>

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<p>Wouldn’t you have to put a “* 2” considering she’s going to be coming back and be taking other routes?</p>

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<p>I tried that way too (lol, and 24 is wrong)</p>

4

<p>Yes, there are 72 possibilities. There are 12 ways to go to Bay Cove (3 x 4), and if you draw a diagram, you can figure out that there are only 6 ways to go back without going on the same road. 12 x 6 = 72. </p>

<p>I answered the exact same question on the thread called Calling All Math Geniuses! </p>

<p>For each way Martina goes to Bay Cove, there are only 6 ways back (draw a picture). There are 12 ways to go to Bay Cove. 12 x 6 = 72.</p>

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<p>^ thanks for the help, i checked your old thread.</p>

<p>:) ill google probability and post if I find stuff (in case any one else is weak in this area also(</p>