217. In a certain game, a large container is filled with red,
yellow, green, and blue beads worth, respectively, 7,
5, 3, and 2 points each. A number of beads are then
removed from the container. If the product of the point
values of the removed beads is 147,000, how many
red beads were removed?
(A) 5
(B) 4
(C) 3
(D) 2
(E) 0
Arithmetic Properties of numbers
From this, the red beads represent factors of 7 in
the total point value of 147,000. Since 147,000 =
147(1,000), and 1,000 = 10 3, then 147 is all that
needs to be factored to determine the factors of 7.
Factoring 147 yields 147 = (3)(49) = (3)(72). Th is
means there are 2 factors of 7, or 2 red beads.
Th e correct answer is D.
看了解释还是不明白，有没有人解释一下？作者: bigbigboy 时间: 2010-4-9 21:37
