Here we go again: QR problem Help!

[HannibalLecter]

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Math Destroyer - Practice Test 10

Problem #2:

If S > log_{5}100,000, what is the smallest integer value of S?

How would we go about solving this problem, I am good at exponents and logs but when it gets combined = me flustered just like damn word problems

 

[rockclock]

well you have a calculator on QR now, right? so just punch in log 100000 / log 5 and round up (in any base as long as they're the same, so ln would work just as well as base 10 log). save a few seconds by recognizing log 100000 = 5 (and use base 10 log for the denominator).

 

[HannibalLecter]

The calculator on the DAT doesn't have log or ln functions. I was looking for the b&m way to do it?

 

[rockclock]

type in 5.
then *5.
then = repeatedly.

keep track of how many times you hit equals and let me know when you break 100000.

p.s. no idea what b&m means...

 

[HannibalLecter]

Nm

 

[rockclock]

Nm

what are you talking about? that's a serious answer. it will work on the standard windows calculator. you do realize you only have to go til 8, right?

 

[FROGGBUSTER]

Well I think I have a way.

5^x = 100,000.

That's the same thing as...

(10^x) / (2^x) = 10^5

Now you start with x = 5. Obviously that will be less than 10^5.
Try x = 6. That's 10^5 * 10/64. Still less. What I'm doing is this: 10^5 * 10^(x-5) / 2^x.
Try x = 7. That's 10^5 * 100/128. Still less.
Try x = 8. That's 10^5 * 1000/256. Finally more.

That's your answer.

 

[HannibalLecter]

what are you talking about? that's a serious answer. it will work on the standard windows calculator. you do realize you only have to go til 8, right?

Rockclock I want to stay away from just inputting it in the calculator because I have heard how bad it lags on the real DAT with sh*tty comps. I don't trust my luck in the real world because I have learned that a long time ago.

Well I think I have a way.

5^x = 100,000.

That's the same thing as...

(10^x) / (2^x) = 10^5

Now you start with x = 5. Obviously that will be less than 10^5.
Try x = 6. That's 10^5 * 10/64. Still less. What I'm doing is this: 10^5 * 10^(x-5) / 2^x.
Try x = 7. That's 10^5 * 100/128. Still less.
Try x = 8. That's 10^5 * 1000/256. Finally more.

That's your answer.

Yea you kinda do have to visualize like that huh. This makes sense still don't understand why you are multiplying each polynomial (ie x = 7, x = n) by 10^5. But I do get the numerator and denominator functions changing and that reflecting in the answer. Ohh I get it, thanks frogger that does make sense now.

 

[rockclock]

Rockclock I want to stay away from just inputting it in the calculator because I have heard how bad it lags on the real DAT with sh*tty comps. I don't trust my luck in the real world because I have learned that a long time ago.



Yea you kinda do have to visualize like that huh. This makes sense still don't understand why you are multiplying each polynomial (ie x = 7, x = n) by 10^5. But I do get the numerator and denominator functions changing and that reflecting in the answer. Ohh I get it, thanks frogger that does make sense now.

you and frog are making this way harder than it needs to be, but fine, I'll play...

log_5(10^5)
= log_5(5^5) + log_5(2^5)
= 5 + log_5(32)
= 5 + 2...

round up to 8

all you need for that is knowing 32 is more than 25

 

[HannibalLecter]

= 5 + log_5(2^5)
= 5 + 2...
= 7...

round up to 8

all you need for that is knowing 32 is more than 25

Got it, thanks dude

 

[rockclock]

I am confused from this point on, doesn't log_5(2^5) equal 2 only?!?!? Why do you have all that gunk after it and why would we round it up to 8?

Where are you getting the 32 from?

seriously?! what kind of crap do they teach you...?

32 = 2^5...you can do it on your fingers if you don't know that...2,4,8,16,32

and log_5(2^5) =/= 2...brush up on what a log is if that seriously threw you

 

[HannibalLecter]

seriously?! what kind of crap do they teach you...?

32 = 2^5...you can do it on your fingers if you don't know that...2,4,8,16,32

and log_5(2^5) =/= 2...brush up on what a log is if that seriously threw you

See dude you have like a natural hate for me and frogger I was just getting confused on the steps you were taking in your solution. You YOURSELF changed some of the steps in your solution. Then I realized it and I changed my post. But you want to get offensive.

 

[rockclock]

Got it, thanks dude

good, but definitely reconsider your no calc policy...that won't do you any favors.

that's coming from someone who got a 30 QR without it btw.

 

[rockclock]

See dude you have like a natural hate for me and frogger I was just getting confused on the steps you were taking in your solution. You YOURSELF changed some of the steps in your solution. Then I realized it and I changed my post. But you want to get offensive.

hahaha relax...i changed 2^5 to 32 because i didn't catch that on the copy and paste...hardly a "change" since 2^5 = 32.

got some history with frogger and you come off as a condescending ass in most of your posts to other people, so i'm just returning the favor

 

[HannibalLecter]

hahaha relax...i changed 2^5 to 32 because i didn't catch that on the copy and paste...hardly a "change" since 2^5 = 32.

got some history with frogger and you come off as a condescending ass in most of your posts to other people, so i'm just returning the favor

Whatever dude you are held to your own opinion but I have never thought of myself greater than anyone else until I prove something of myself even then I won't be putting down anyone else just to raise my stature.