问三道GWD数学题目：23/31的题目。

Q27:

If line k in the xy-plane has equation y = mx + b, where m and b are constants, what is the slope of k ?

(1)       k is parallel to the line with equation y = (1 – m)x + b + 1.

(2)       k intersects the line with equation y = 2x + 3 at the point (2, 7).

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

我觉得选C 啊， 答案是A;

Q33:

If 10⁵⁰ – 74 is written as an integer in base 10 notation, what is the sum of the digits in that integer?

A.  424

B.  433   

C.       440

D.      449

E.       467

C

我算的是(50-2)x9+2+6

Q35:

What is the greatest common factor of the positive integers j and k?

(1)       k = j + 1

(2)       jk is divisible by 5.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

这个答案是A, 我想可能是它认为相邻的互质？ 但是题目并没有告诉J, K 的值啊？

请解答，谢谢！

1. 因为slope of K line =m 由(1)因为平行线斜率一致，推出m=1-m，可算m （2）相交线不足以算斜率 所以选A

2. 10^50-74=99……26 一共有多少个9捏，一个有48个9，因为10^50有51位（1个1和50个0），减去个两位数，剩50位，包含28个9，1个2和1个6，所以48*9+2+6=440

3.我选了C 所以同求解

Q35:

What is the greatest common factor of the positive integers j and k?

(1)       k = j + 1

(2)       jk is divisible by 5.

两个相邻的正整数不会有相同质因子阿，所以条件1单独就已经可以充分推出j,k只有1这个公因子, 答案a

两个相邻的正整数不会有相同质因子阿，所以条件1单独就已经可以充分推出j,k只有1这个公因子, 答案a