@legalpad12 If you did the grid-ins first followed by the MC questions, how would your brain feel by the end of the MC section?
Because the questions are all worth the same amount, it’s generally a good idea to knock off the easiest/fastest questions first so that you have more time for the harder ones, while being careful not to rush too quickly. I always just did the test (old SAT) in order. You should do whatever suits you best.
Here’s an approach you may want to try: Go through about the first 2/3 of the multiple choice followed by the first 2/3 of the grid ins. Then go back and finish the multiple choice, then finish the grid ins.
Now this approach assumes that you’re currently scoring at least 630 on official practice tests. If you’re scoring less, then you should NOT be attempting every question. In this case I have a table I created that describes how many of each question type you should be attempting in each section.
Jill and matt began at the same point but ran around the track in opposite directions. Jill ran at a constant speed that was 2 meters faster than Matt’s constant speed. jill passed Matt for the first time in 40 seconds. Jill ran at a constant rate of how many meters per second? (400 meter long track, they run 10 laps daily)
A4
B5
C6
D7
E10
Correct answer is C
if n!/(n-2)! = 30, then (n-1)!=
A15
B24
C60
D120 (correct)
E720
I got this one right but I was wondering why it couldn’t be another answer as well?
what forms f(gx))= square root of 2X^2+3
f(x) = square root of x, g(x) = 2x^2+2
and this was wrong but why? f(x)= square root of x^2+3, g(x)= 2X
@xxupenngal If g(x) is 2x then plugging 2x into x^2 + 3 would result in square root of (4x^2 + 3), not square root of (2x^2 +3).
do i need to memorize the cosine of 180 degrees? help bc otherwise I dont get the explanation that is given
There is a small chance that a question could come up on the SAT where you will need to know how to evaluate a trig function at a quadrantal angle (the quadrantal angles are 0, 90, 180, and 270 degrees). There are several ways to do this without memorization.
One way is to Just look at the appropriate point on the unit circle (the circle with radius 1 centered at the origin). We always start at the positive x-axis. The cosine of an angle is the x-coordinate of a point on the unit circle. We get to that point by rotating around by that angle. So cos 180 is the x-coordinate of the point on the unit circle that is also on the negative x-axis. So it’s -1.
An ongoing promotion at a department store gives customers 20% off the portion of their bill that is over $100. Ruby’s total bill at the department store after the promotion has been applied is $250. If x represents the amount of money Ruby would have spent on the same purchase at the department store without the promotion, which of the following equations best models the situation? The answer: 100+0.8(x-100)=250 Can someone explain why x-100 represents the cost to which the discount applies? And why it added pre-sale $100? I can’t get it
It might help to walk through with a specific x-value. Let’s let x = 110. So Ruby would have spent $110 without the promotion. Now for the promo, we take 20% off the portion of the bill over $100. In other words, we take 20% off $10. How did we get 10? Well 10 is 110 - 100. This is where the x-100 comes from, We need to subtract 100 before applying the discount because the discount is only on the portion over $100.We now apply the discount. Taking 20% off of something is the same as taking 100 - 20= 80% of that thing. So we have 0.8(x-100). So we applied the discount to the the $10. But the price wasn’t $10. It was $110! What happened to the other 100? Well we subtracted it off before applying the discount. But we still have to pay it. So we add it back!
omg, now i get it, i thought i had to take 20% off the whole value. thank you! =D>
Hey Could Someone help me with question #10 in the college panda book. It’s number 10 in the exercises at the end of chapter 1: exponents and radicals. This chapter is free on the college panda website as a sample with answer explanations. I understand the explanation except the part where the factoring out occurs.
@markj4994 you mean this problem?
The first step is to split up 2^{x+3} as 2^x * 2^3 (or 8*2^x) using the exponent rule a^{b+c} = a^b * a^c.
Then you can factor out 2^x since the LHS contains two terms containing 2^x.
Sorry for late reply but thank you. You helped!
If a certain number is 3 more than 7 times itself, what is the number?
A. -3
B. -3/2
C.–1/2
D. -3/8
Can someone tell me what they think the right answer is for this question and why. I keep getting the wrong answer for this problem and do not understand what to do. Thanks
Here is a quick algebraic solution:
x = 7x + 3
0=6x + 3
-3 = 6x
-3/6 = x
-1/2 =x, choice C
You can also solve this by plugging in the answer choices, but it’s a bit messy because of the fractions (especially if this is a no calculator problem).
Okay. Thanks!
Are there typically questions like the one I just posted on the SAT. @DrSteve
Yes. That seems like it could be an actual SAT question.
@wildguy57 the ability to translate those word problems into an algebraic problem (which could be solved more routinely) is extremely useful on the SAT.
Another example: Mike bought two pencils and three pens for $1.70. John bought one pencil and five pens for $2.25. How much does one pen cost, in cents?
Setup a system of equations, let x be pencils and y be pens:
2x+3y=1.7
x+5y=2.25
Subtract 5y from both sides of the last equation to get x in terms of y:
x=2.25-5y
Plug this value for x into the first equation:
4.5-10y+3y=1.7
And solve for the (the cost of pens) to be .4, which equals 40 cents.
You could also solve this using a matrix, btw.
Here’s a good one:
What is the value for x, to the nearest thousandth, which satisfies the equation below?
3.6^(4x+8)=463
@kimclan1 True, though systems of equations on the SAT are often simple enough that using Cramer’s rule or any other method involving matrices is not needed.