I think Brad mentioned that he's taking every test from 1990-2006, which means enough tests to keep him occupied the entire summer: 5 tests / year * 16 years = 80 tests to take. Which means all summer long... I say that we all do the same, and keep up a test score log to see how we improve/stack up against others. If its too much trouble for everyone, I understand, but I thought it would be a good idea.
Anyways, I had a few questions from STH -1 April 14, 2005.
14) 18.75% of 32 is _____________
I did this by foil, but it took me waaaaaaaay too long to get the right answer. Faster way?
18) 5/12 - 12/5 = _______________.
I know the trick for adding fractions in that form, but whats the subtraction trick?
29) 74^2 + 33^2 = _______________.
I dont see any relationship at all between those two numbers. How do you do it?
14) MEMORIZATION --> the fraction of 16th: 18.75% = 3/16, so the answer is 6
18) well, if you expand b/a - a/b = (b^2-a^2)/ab = (b-a)(b+a)/ab, -17*7/60 = -119/60 = -1 59/60, I doubt if that would work any better if ab is nastier.
29) the relationship is the outer numbers' sum is 10, and the inner numbers are consecutive. The shortcut is 101*sum of squares of each of the number's digit. So the answer is 101*(7^2+4^2) = 101*(49+16) = 6565. I ask YOU to prove it algebraically, and tell me how to determine which is the number.
I have a .txt file of all my scores on practices tests since I started practicing ( about 225 tests) It's pretty cool to see that i've gone from 120s to scores consistently between 250 and 350
btw.. 5 tests per year I take 7 per year
I'm working on making a 2007 test similar to the 2005 test on Dr. Numsen's site. I'm going to come into next year having everything about 2007 memorized.
Sorry its taken me so long to post back, Sam, but I've been busy with soccer tryouts and SAT classes. I didnt want to pass up an oppurtunity to derive a shortcut as cool as this one.
For adding squares in the form: (xy)^2 + ((y-1)(10-x))^2 ie outsides add to 10 and inners are consecutive.
Since we used y and y-1 to derive the equation, and the final answer only included y, the number you use is the one with the bigger y, or biggest inside number.
I take 7 per year 
