Jan SAT Math Help

Discus: SAT/ACT Tests and Test Preparation: March 2004 Archive: Jan SAT Math Help
 By Charmedprue (Charmedprue) on Sunday, March 07, 2004 - 01:30 pm: Edit

When I got my booklet back, I redid all my questions but there were still a few I didn't know how to get, so can y'all help me?

23. A sales representative traveled at an average speed of r miles per hour for 4 hours and then at an average speed of s miles per hour for 6 hours. What was the average speed, in miles per hour, for the entire trip?
B) (2r+3s)/5

Can you also tell me what this problem is saying b/c I don't understand it:

24. A= {1,2,3,4,6,9,12}
Set A above has the property that, for each number in the set, all positive integer factors of that number are also in the set. Which of the following numbers could also be included in the set so that the new set of eight numbers would still have this property?
I. 8
II. 11
III. 15

Also, I hate geometry so I really don't know this one. This is without a picture so I don't know if y'all can get it, or if some of you who took it on Jan. can remember it.You might want to look at the question first, because I might be repeating stuff in the question since I don't know exactly what inscribed means.

22. THE FIGURE: is of an equilateral triangle inside of a dotted circle with only the three points touching the circle. The triangle is pointed downwards. The dotted circle is inside of a square with four sides of the circle touching. You know, kind of like you can only see the four points of the square that looks like triangle (except for the part with the dotted circle).
Anyway, the left point of the triangle is A, the right is B, the bottom is C. The left side of the circle, the one touching the square, is D, the right side F, the top is E, and the bottom is C. (Notice that both downward pt of the triangle and the bottom part of circle is C.) There is a solid arc, BF, if y'all draw the figure right.

THE QUESTION:
In the figure above, equilateral triangle ABC is inscribed in the circle. The circle is inscribed in the square so that points C, D, E, and F are on both the circle and the square. If the circumference of the circle is 240 inches, how long, in inches, is the solid arc BF?

 By 31337 (31337) on Sunday, March 07, 2004 - 04:28 pm: Edit

For question 23
remember that Average speed = total distance/total time

total distance = speed * time
so total distance becomes 4 * r + 6* s
total time = 4 + 6 = 10

avg speed = (4r + 6s)/10 = 2(2r + 3s)/10 = (2r +3s)/5

The question 24 says that you need to insert such numbers whose factors are already present ( or will become present if the number added is a prime). You can add 8 because it's factors (1,2,4 and 8) will be present. You can add 11 aswell since 11 is a prime and will therefore have its factors in the set. You can't add 15 because you're missing one of its factors i.e. 5. I can't help you with the last question since I went with a longer route and it can easily confuse you BUT I did get the correct answer..

Hope this helps.

 By 31337 (31337) on Sunday, March 07, 2004 - 04:28 pm: Edit

For question 23
remember that Average speed = total distance/total time

total distance = speed * time
so total distance becomes 4 * r + 6* s
total time = 4 + 6 = 10

avg speed = (4r + 6s)/10 = 2(2r + 3s)/10 = (2r +3s)/5

Question 24 says that you need to insert such numbers in the set whose factors are already present ( or will become present if the number added is a prime). You can add 8 because it's factors (1,2,4 and 8) will be present. You can add 11 aswell since 11 is a prime and will therefore have its factors in the set. You can't add 15 because you're missing one of its factors i.e. 5. I can't help you with the last question since I went with a longer route and it can easily confuse you BUT I did get the correct answer..

Hope this helps.

 By Charmedprue (Charmedprue) on Sunday, March 07, 2004 - 07:10 pm: Edit

Thanks 331337, I greatly appreciate the help.

Anyone know an easy way to get question 22? I have been trying this problem for hours (really for three hours) because me and my parents were arguing how to get it.
Anyway, if someone doesn't actually want to do it, can you at least tell me some theorems/rules about inscribed angles and arcs?

 By Neelesh (Neelesh) on Sunday, March 07, 2004 - 07:14 pm: Edit

hey charmedprue..i have a question.
can you send me a copy of the test? please???
by email

 By Charmedprue (Charmedprue) on Sunday, March 07, 2004 - 08:01 pm: Edit

I'm sorry Neelesh but I don't have a scanner so I can't send it to you.