[求助]几道og资充题?

fernandochang

英文解释看不懂!!! 请帮忙! 谢谢! 272. In the fraction x/y, where x and y are positive integers, what is the value of y? (1)The least common denominator of x/y and 1/3 is 6. (2)x=1 A):E 268. Henry purchased 3 items during a sale. He received a 20 percent discount off the regular price of the most expensive item and a 10 percent discount off the regular price of each of the other 2 items. Was the total amount of the 3 discounts greater than 15 percent of the sum of the regular prices of the 3 items? (1)The regular price of the most expensive item was $50, and the regular price of the next most expensive item was 20. (2)The regular price of the least expensive item was $15. A):A 266.Marta bought several pencils. If each pencil was either a 23-cent pencil or a 21-cent pencil, how many 23-cent pencils did Marta buy? (1)Marta bought a total of 6 pencils. (2)The total value of the pencils Marta bought was 130 cents. A):B 264.Is 2x-3y2 and y>0 A) 263. Is m≠n? (1)m+n<0 (2)mn<0 A):B

jinbaiying

272
1. yw(因为): the least common denominator of x/y and 1/3 is 6, i.e. x/y and 1/3 的最小公共分母是6，x/y were x/2 or x/6.
sy(所以) : (1) is not sufficient.
2. (2) is not sufficient.

sy: E


其他OG讲的比较清楚