More Maths ! Help!!

Test Preparation SAT Preparation
1

<p>can anyone please explain these nasty questions ?! i would appreciate your feedback</p>

<p>*If the length of AB is 5 and the length of BC is 6 which of the following could be the length of AC?
a 10
b 12
c 13
d 15
e 18</p>

<ul>
<li><p>Fifty percent of the songs played on a certain radio are 3 minutes long. Thirty percent of the songs are 5 minutes long and twenty percent of the songs are 2 minutes long. What it the average mean of the number of minutes per song played on the radio station?</p></li>
<li><p>A large solid cube is assembled by gluing together identical cubic blocks . all six faces are painted red. if exactly 27 of the small blocks have no paint on them . then how many small blocks make up the large cube??</p></li>
</ul>

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<p>i would reeeaaallly appreciate your guidance</p>

2

<ol>
<li><p>AB + BC >= AC so (a) is the only option that works.</p></li>
<li><p>Convert the percentages to decimals: 50% = .5, 30% = .3, 20% = .2. Then the mean song length is the weighted average 3 (.5) + 5 (.3) + 2 (.2) = 3.4 .</p></li>
<li><p>The unpainted cubes together form an inner cube of dimension 3x3x3. Adding a layer of painted cubes on the outside of this, you get a 5x5x5 . So that's 125.</p></li>
</ol>

3

<p>i get q2 but the other answers are too brief i dont get them can u get in to details :( ??</p>

4

<p>The length of the two smaller sides on a triangle must add up to MORE than the length of the largest side.</p>