SAT Math Questions

Test Preparation SAT Preparation
1

<p>I have some SAT math Q's.</p>

<p>1)
The number n if a 2-digit number. When n is divided by 10, the remainder is 9 and when n is divided by 9, the remainder is 8. What is the value of n?</p>

<p>First I put this problem in the n=10k+9 and n=9m+8. n is the top of the fraction, 10 and 9 are the bottom of the fraction. 9 and 8 are the remainders.</p>

<p>I didn't exactly get how to solve the problem using this equation(if they are correct).</p>

<p>But in the end, I was able to reason out that the answer was 89 because only 19,29,39,49,59,69,79,89,and 99 would satisfy the "n is divided by 10, the remainder is 9" portion. And 89 was the only number to satisfy the "n is divided by 9, the remainder is 8" portion.</p>

<p>2)
When a certain odd number is divided by 5, the remainder is 1. Which digit must be in the units place of this odd number?</p>

<p>so my set up was:
odd number=5Q+1</p>

<p>I don't know how to approach this problem from this equation(if its correct).</p>

<p>I was able to reason out that the answer is "1" but I'm looking for faster ways to solve remainder problems. They always trip me up in the math portions.</p>

<hr>

<p>I've already competed Gruber's Complete Review Book for the SAT(I did the math portion only). Right now, I am improving in SAT math mainly by doing sat online course test math portions slowly and figuring out the answers. I can solve all of the problems but I tend to make mistakes under timed conditions. Will I really begin to see familiar patterns in math questions as I do more practice tests? I'm on my 3rd test right now..</p>

2

<p>hey, #1 is actually an interesting problem to me.</p>

<p>89 is correct, but when i did it, i got 90 for some odd reason</p>

<p>what i did was
n/10 = 9</p>

<p>but im still a sophmore in HS and suck with problems like these. so i just got N by itself and multiplied the 10 into the 9.</p>

<p>idk =(</p>

3

<p>These are the methods I used to solve those problems, but they may not be the best/most efficient.</p>

<p>For the first one, I used the follow logic: the number needs to be a multiple of both 9 and 10, minus one, because the remainders are one less then their respective divisors. The smallest number that is a multiple of both 9 and 10 (LCM) is 90, and 90-1=89.</p>

<p>For the second one, I used your equation. Q must be an even number for the equation to simplify to an odd number. Plug in any even number for Q, then, and you’ll see that the resulting number’s units digit is always 1.</p>

4

<p>Hello,
There are many ways to do a problem.
For the first one dear Rasd.

  1. n/10=9, so n=90…again n/9=8 so n=72
    so n must be within this range and only 89 fits in. SO your answer is correct. Dont go to form equations as you can see that in your equation there are three unknown k,n and m. But you have only two eqns. So you can never solve it.</p>

<p>2) all the numbers like 11, 21, 31, 41…will take the answer as only 1. And yes you are very correct to get the answer as 1.</p>

<p>Best of luck.
Cheers.
I am stuck in my writing section. If u can then please help.</p>

5

<p>Sure, although offtopic. I think the consensus of the CC is to read sparknotes seven deadly screwups : <a href=“http://www.sparknotes.com/testprep/books/newsat/chapter8section3.rhtml[/url]”>http://www.sparknotes.com/testprep/books/newsat/chapter8section3.rhtml&lt;/a&gt;&lt;/p&gt;

<p>Also get rocket review if its available and read the grammar section. You might want to check out page 110ish or so? in the blue book for a list of grammar. I think practice is key…I have pretty bad grammar scores right now so I’m not the right person to ask advice haha :)</p>