questions from topscore 2

[sherry225]

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A couple of the math questions on topscore 2 was pretty difficult. (well, at least for me 🙁 ) Here are a couple that I still have no clue....

1. there are 3 yellow roses, 2 pink roses, and 5 red roses, how many 3 rose arrangement are there? Answer is 120

2. what's the third term after you expand this (x+3)^5
answer: 90X^3 (what's the easiest way to do this without actually expanding them?)

3. what's the probability of getting consecutive heads or tails in 4 tosses of a coin? Answer:1/16 (Why isn't it 1/8 since it's asking all heads or tails...?)

Chem Question:
what volume of HCl was added if 1M NaOH is titrated with 1M HCl to give a PH of 2? (the answer of topscore was none of the above, but does anyone know what will the answer be? I just want to make sure I can do this....)

Bio:
I didn't know snails have hydrostaticskeleton too???????



~~~~~Seriously frustrated!!! 😕

 

[drat]

1. http://forums.studentdoctor.net/showthread.php?t=128388&highlight=yellow+roses

3. 1/2 probability for each flip...4 flips so (1/2)^4 = 1/16

I think you just made a mathematical error because your thinking was right on...(1/2)^3 = 1/8

 

[drat]

2. what's the third term after you expand this (x+3)^5
answer: 90X^3 (what's the easiest way to do this without actually expanding them?)


~~~~~Seriously frustrated!!! 😕

I have an answer for this, too, but it will take awhile to type out and I have to shadow my dentist in 20 min. 🙂 So when I return and this hasn't been answered, I'll help you out. The trick is using Pascal's triangle.

 

[sherry225]

3. 1/2 probability for each flip...4 flips so (1/2)^4 = 1/16

I think you just made a mathematical error because your thinking was right on...(1/2)^3 = 1/8

I got 1/8 because I multipy 1/16 by 2 (purposely) because it said in the question what'd the probability for gettting all heads "OR" all tails......so there are twice as much chance of getting it than just all heads or just all tails........is my reasoning wrong??? 😕

 

[sailinx]

Hi,
I just posted the answer to the chemistry question at the following link. Take a look.

http://forums.studentdoctor.net/showthread.php?p=1734150&posted=1#post1734150

 

[jk5177]

I'm sorry you are frustrated with the studying. That was exactly how I felt a while back. Those problems you are posting now are EXACTLY THE SAME ONE'S I STRUGGLED WITH TOO.

It seems like you are on the right track, that is... trying to figure out problems that you missed. However, some of the problems are really really hard on the topscore, and I didn't even see any questions to that degree of difficulty on the actual test. So, I wouldn't waste any energy being frustrated about these "high-end difficult" problems which people who score over 25 would get right. What's important is to KEEP STUDYING THE IMPORTANT MATERIALS AND DON'T GET EMOTIONALLY BOGGED DOWN.

That being said, let me look at the problem. The (x+3)^5, and what is the fifth term requires using the Bionomial Theorem for expansion. See:

http://www.mathsdirect.co.uk/pure/purtutbinpas.htm

I don't know of any short cuts that would be faster. But, I seriously wouldn't lose sleep over this problem. Good luck, and enjoy the preparation.

 

[sherry225]

Hey guys,

Do snails really have hydrostaticskeletons? I thought they have exoskeletons???

 

[drat]

That was a great link jk posted...I was going to type all of that out. If you are still having problems with expansion, PM me. I can help you out. But as someone already posted, these are more difficult that the actual DAT. As long as you can do FOIL, you're good to go for the DAT. 🙂

 

[weiy01]

Hey guys,

Do snails really have hydrostaticskeletons? I thought they have exoskeletons???

They have both. They use a hydrostatic skeleton that is used for locomotion/movement and the hard shell that snails possess makes it an exoskeleton. Phylum Arthropoda also has an exoskeleton.

I got this online 🙂. There are quick answers that you can get by doing a google search. Hope this helps🙂

Im also taking my test in a week

 

[sherry225]

Thanks everyone! 🙂