Math Problems I'm struggling with

[Guest]

1)
Arithmetic sequence t1, t2.....tn. t1 = 23 and tn=tn-1 - 3 for each n>1
Find n when tn = -4

Please go through how to solve this problem. The answer is 10.

2)
Are X and Y both positive?
a)2x+ 2Y =1
b)x/y > 1

Please go through how to solve this problem. The answer is C.

3)
B


A D C

For triangle ABC find side BC. Angle A is X. Angle D is 2x and angle C is 2x.
1)Line segment AD is 6
2)X = 36

Please go through how to solve this problem. The answer is A. I understand if this isn't clear due to the image. But A (x degrees), B, and C (2x) are the corners of the triangle and there is a line between B and D (2x).

4)
For students in class A, the range in heights is r and the greatest height is g.

For students in class B, the range in height is S and the greatest height is h.

Is the least height in class A greater than the least height of students in class B?

1) r<s
2) g>h

Please go through how to solve this problem. The answer is C.

5)
If the speed of X meters per second is equivalent to the speed of Y kilometers per hour. what is Y in terms of X? (1 kilometer = 1,000 meters)

Please go through how to solve this problem. The answer is 18x/5.

6)
Equilateral triangle ABC is inscribed in a circle. The length of arc ABC is 24. What is the approx. diameter of the circle?

Please go through how to solve this problem. The answer is 11.

I know I have a lot of questions so thank you in advance. I was just shocked at how lost I was during the practice exam in which these appeared.

[rfernandez]

Please indicate the source of the problems. Also, please post only one problem per post. (Refer to the sticky for all guidelines.)

Thanks.

Rey