可汗
12.Paper Scraper, Inc, a mobile paper shredding and recycling company, receives $0.39 for each pound of paper they shred, but it costs them approximately $1.38 per mile to operate their truck. Any job that requires less than 200 miles of travel, and also nets at least $500 profit, qualifies for free delivery. Of the following, which combination of size in pounds and distance in miles would qualify for free delivery?
A. Paul has 1,100 pounds of paper that requires 3 miles of travel.
B. Li Min has 1,500 pounds of paper that requires 107 miles of travel.
C. Amira has 1,800 pounds of paper that requires 94 miles of travel.
D. Jarles has 3,500 pounds of paper that requires 225 miles of travel.
CORRECT ANSWER: C DIFFICULTY LEVEL: 2
13.When Suraj goes to Roycefield golf course, he loses 20% of the (golf) balls he uses. When he goes to Hunterdon golf course, he loses 30% of the balls he uses. It costs Suraj $1.20 to buy a ball. This weekend, Suraj is planning to use 25 balls at Roycefield and 30 balls at Hunterdon. If he only has $20 to spend on balls, how many balls can he buy in order to guarantee that he will be able to replace the balls he loses this weekend?
A. 5
B. 10
C. 15
D. 20
CORRECT ANSWER: C DIFFICULTY LEVEL: 2
14. A technology store sells tablets and computers. In January they sell over 300 items, and more of those sales are tablets than computers. In February they sell exactly 100 tablets and 20 computers. The graph at left shows two equations related to this problem, where t is the total tablet sales (in January and February combined), and c is the total computer sales. Which of the following combinations could be the technology store's total sales?
A. 240 tablets and 100 computers
B. 360 tablets and 180 computers
C. 240 tablets and 260 computers
D. 120 tablets and 180 computers
CORRECT ANSWER: B DIFFICULTY LEVEL: 2
15.Elena is designing a paint can with thickness t millimeters and height h centimeters. She calculates that the thickness of the can in milimeters must be at least 0.1 times the height of the can in centimeters in order to withstand pressure. Due to cost constraints, the cost of material used, (0.2+t+0.5h) cents, must be at most 12.2 cents. Which of the following systems of inequalities best models the relationship between height and thickness described above?