Official Solution:
Out of the total pigs in the study, male pigs are 80%, and some pigs caught a cholera. 50% of pigs that caught a cholera are males, and the total number of the male pigs in the study is x times of the male pigs that caught a cholera. Also, the total number of the female pigs in the study is y times of the female pigs that caught a cholera. What is the value of \(\frac{x}{y}\)?
A. 9:2
B. 6:1
C. 8:1
D. 4:1
E. 8:3
This question is a 2 by 2 question, which appears most frequently in the current Gmat math, as shown in the table below.
Study (100) Catch cholera (10) NOT catch cholera Males (80) 5 Females (20) 5
This is a % question. If you assume that the total number of pigs in the study as 100, since 80% are males, males=80 and females=20. Amongst these pigs, it said that some pigs caught a cholera, and the word "some" means that the answer will be the same regardless of the number of the pigs that caught a cholera, so we will just assume the number of pigs that caught a cholera as 10. If so, 50% of the pigs that caught a cholera are male, so 5 male pigs caught a cholera, and the other 50% becomes 5 female pigs that caught a cholera. So from \(80 = x(5)\), you find \(x = 16\), and from \(20 = y(5)\), you find \(y = 4\).
Hence, \(\frac{x}{y} = x:y = 16:4 = 4:1\). Therefore, the answer is D
Answer: D