SAT官方数学习题 8月25日

来源: 作者: 时间:2009-09-28 Tag: 点击:
SAT官方数学习题 8月25日
Read the following SAT test question, then click on a button to select your answer.

Troy bought a bag of 20 marbles for $2.00, a bag of 50 marbles for $4.00, and a bag of 100 marbles. If the average (arithmetic mean) cost of the marbles in all three bags was exactly $0.08 each, what was the price of the bag of 100 marbles?

A.     $7.00
B.     $7.20
C.     $7.40
D.     $7.60
E.     $7.80

Correct Answer: D

  • Here's Why:

    If the average price of all 20 + 50 + 100 = 170 marbles was exactly $0.08 each, then the total price of all the marbles was (170)(.08) = 13.60 dollars. Therefore, the price of the 100-marble bag was 13.60 – 2.00 – 4.00 = 7.60 dollars.

  • Difficulty: Medium
  • Question Type: Standard Multiple Choice