Directions For the following question, consider each of the
choices separately and select all that apply.
多选题
If the lengths of two of the sides of a triangle are 9 and 10, which
of the following could be the length of the third side?
Indicate all such lengths.
Indicate all such lengths.
【正确答案】
B
【答案解析】By the triangle inequality (KEY FACTS J12 and J13),
· The third side must be less than 9 + 10 = 19. (C is false.)
· The third side must be greater than 10 - 9 = 1. (A is false.)
· Any number between 1 and 19 could be the length of the third side. (B is true.)
多选题
If p pencils cost c cents at the same rate, how many pencils can be bought for d dollars?
【正确答案】
E
【答案解析】Since p pencils cost c cents, each pencil costs [*] cents. By dividing the number of cents we have by [*] , we find out how many pencils we can buy.
Since d dollars equals 100d cents, we divide 100d by [*], which is equivalent to multiplying 100d by [*]
You will probably prefer the alternate solution below.
**Use TACTIC 2, Chapter 9. Assume 2 pencils cost 10 cents. So, pencils cost 5 cents each or 20 for one dollar. So, for 3 dollars, we can buy 60 pencils. Which of the choices equals 60 when p = 2, c = 10, and d= 3?[*]
多选题
Because her test turned out to be more difficult than she intended it to be, a teacher decided to adjust the grades by deducting only half the number of points a student missed. For example, if a student missed 10 points, she received a 95 instead of a 90. Before the grades were adjusted the class average was A. What was the average after the adjustment?
【正确答案】
A
【答案解析】If a student earned a grade of g, she missed (100 -g) points. In adjusting the grades, the teacher decided to deduct only half that number:[*] So the student's new grade was[*]
Since this was done to each student's grade, the effect on the average was exactly the same.
The new average was[*]