Quote:
carcass wrote:
In a certain medical survey, 45 percent of the people surveyed had the type A antigen in their blood and 3 percent had both the type A antigen and the type B antigen. Which of the following is closest to the percent of those with the type A antigen who also had the type B antigen?
A. 1.35%
B. 6.67%
C. 13.50%
D. 15.00%
E. 42.00%
dyee630k wrote:
Why can't the trick .45 * .03 be used here?
dyee630k - The key phrasing is not easy to translate.
If you had a Venn diagram, with a circle for A only, a circle for B only, and overlap of A and B, the question asks what percentage of circle "A only" the overlap "A and B" is.
Let's say 100 people, so
45 = A only
3 = A and B
"the percent of those with the type A antigen [45] . . . who also had the type B antigen? [3]" IS WHAT?
Or, "What percent of 45 is 3?"
Or, "3 is what percent of 45?"
The
percentage is the variable: (\(\frac{x}{100}\))(45) = 3
\(\frac{x}{100}\) = \(\frac{3}{45}\)
45x = 300
x = 6.67
Hope it helps.
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