<p>Ah, thank you. I didn’t understand why one of the scores would be 6.0.</p>
<p>And what does “C” mean in your post, shauryagupta? As in “15C3 - 5C3”</p>
<p>C as in combination, eg, 5C3, choose 3 out of 5</p>
<p>look you have 2 numbers, for 1 to be min, other has to be to its maximum value (in this case 6). Its like a relation, if one is maximum in an equation, other one will always be at min.</p>
<p>shauryagupta’s question
i dun get it why do you have to multiply 1/9, i understand the part why you have to factor 7.</p>
<p>by factoring out 7, you get ( .1 + .11 + .111 + .1111 …)
Now, to make a GP, you need to convert it into, a sequence with a constant multiple.</p>
<p>= 7/9 * ( .9 + .99 + .999 + .9999…)</p>
<p>= 7/9 * ( 1-.1 + 1-.01 + 1-.001 …)</p>
<p>= 7/9 * ( 1+1+1…(20 times) - ( .1 + .01 + .001 + .0001…(up to 20 times) )
= 7/9 * (20 - ( .1(1-.1^20)/(1-.1) ) ) )
= 7/9 * (20 - .111111111…)
= 7/9 * ( 19.888888…9)
= 15.4691358</p>
<p>If you dont multiply and divide by 9 you won’t get a GP.</p>
<p>@shauryagupta it should be pretty obvious that .1 + .01 + .001 + … = .11111…1 (without using the formula for a geometric series).</p>
<p>it was but then it was supposed to be done through GP so…</p>
<p>did you write the questions yourself?</p>
<p>Nah, I had done them as a practice for JEE (Joint Entrance Examination) in grade 11th, so i remembered them.</p>
<p>Ah. They don’t look too difficult (about the same level as mid AMC12 problems), but definitely harder than SAT II.</p>
<p>So, I just took my first Barron’s practice test and got a 640. </p>
<p>Oh dear god I’m freaking out. I really need a 780+ on this thing</p>
<p>First time on Barron’s with a 640 is good. Just practice more and you can definitely reach 700+ on Barron’s which is actually quite impressive.</p>
<p>*This is just JEE Mains. If any1 wanna test themselves at P,C or Maths, i suggest you try doing JEE Advanced (without using a calc as you aren’t allowed calc on it). </p>
<p>Search JEE Advanced paper 2013 or just JEE papers (before 2013 it was known as JEE)</p>
<p>JEE Advanced is one of the toughest examinations of PCM ,at a school level ,in the world.</p>
<p>McGrawHill is notoriously famous for being easy and rife with errors…My friend used it to study for the November Math II.she got a 750+ on the practice tests but got a 650 on the real thing…I wouldn’t touch that book…</p>
<p>Is The Official SAT Subject Tests in Mathematics Levels 1 & 2 Study Guide worth buying? How many math 2 test in there?</p>
<p>Got a question:
If the length of the side of tetrahedron is 2cm, its volume is</p>
<p>A.(2√2)/2 cm^3
B. (4√6)/9 cm^3
C. (4√8)/9 cm^3
D. (2√3)/3 cm^3</p>
<p>tetrahedron made up of equilateral triangles?</p>
<p>if yes the formula is a^3/(6*(root2))</p>
<p>which means 8/(6root2) = 2root2/3 cm^3</p>
<p>which is not there in the options</p>
<p>no…this is a question from Hong Kong public exam. I’m sure there is answer.
i’m sure this question is not that easy. cuz it includes concepts like circumscribed and 3d trigonometry.</p>
<p>The area of the base (one of the faces) is sqrt(3). To find the height, drop a segment from the top vertex to a midpoint of one of the sides, i.e. you should obtain a right triangle with sides sqrt(3)/3, h, and hypotenuse sqrt(3), so h = sqrt(8/3) = 2sqrt(6)/3. The volume is (1/3)<em>sqrt(3)</em>2sqrt(6)/3 = 2sqrt(2)/3. Not in the answer choices.</p>