So far, Hua has received 1,350 + 900 = 2,250 surveys. Hua needs 3,800 – 2,250 = 1,550 additional surveys. Given that Hua receives 1 completed survey for every 5 she sends out, she will need to send out at least 5 × 1,550 = 7,750 surveys. Therefore, the correct answer is (C).

Since line AE is perpendicular to the line containing segment AB and the line containing segment DE, these two lines must be parallel. Therefore, ∠ABC is equal to ∠CDE because they are both small angles created by a line crossing two parallel lines. Since ∠DCE and ∠ACB are opposite each other, they must be equal as well, so these are two similar right triangles. The question also tells you that C is the midpoint of BD, which means that BC and CD are equal. When you have two sides and the included angle of one triangle congruent to two sides and the included angle of a second triangle, you know that the triangles are congruent. This means that AB = DE and AC = CE. Lastly, the question states that AC = DE, which means that AB = AC, and these must be isosceles right triangles. Angle ABC is therefore 45°, and n, which is opposite ∠ABC, must be 45° as well. The correct answer is (B).

Start with the easier equation and use Process of Elimination. The easier equation is related to the total number of turkey and bread slides, t + b, on the 4 platters. According to the question, each platter contains 100 slices, so the 4 platters contain 100 × 4 = 400 slices. Therefore, one of the equations in the correct answer must be t + b = 400. Eliminate (A) and (B) since neither of these answers contains that equation. The second equation deals with the weight of the slices. According to the problem, the slices on each platter weigh 160 ounces. Therefore, the total weight of the slices on all 4 platters is 160 × 4 = 640. Eliminate (C) because the total is wrong in the weight equation. The correct answer is (D).

Whenever there are two equations with the same two variables, they can be solved simultaneously by adding or subtracting them. The key is to get one variable to disappear. Multiply the second equation by -2, to get 6a – 2z = 20. Stack the two equations and add them. Therefore, the correct answer is (D). Be careful of (C)-the question did NOT ask for the value of a.

We know that Isabella starts with $1,000 in her account, so this eliminates (D). She is earning money from the interest, so the line must have a positive slope, eliminating (C), which has a constant slope. The two best choices are (A) and (B), but in (A) Isabella’s money doesn’t begin to increase until the 5-year mark, which doesn’t make sense-thus (B) is the best choice.