十月机经（三）

tongxun

感谢前台发机经的无名兄弟！！！ ================================================ 1、(1/2)(2/3)(3/4)(4/5)(5/6)(6/7)(7/8)=? JJ ---------------------------------- 1/8 ========================== 2、A bookstore sold 100,000 hardbooks first. Then it sold 200,000 hardbooks and softbooks. The number of the softbooks is 3 times as much as hardbooks which is sold the second time, and the price of a softbook is 1/3 of that of a hardbook. What is the percentage of the sales of softbooks in the total sales. JJ --------------------------------------- 1/4 或25% ======================================= 3、4 groups have 10, 10, 10, 20 members individualy. Choose 1, 1, 1, 2 persons from each group. How many posibilities? ---------------------------------------------- 190,000 ================================================== 4、A truck is traveling at a speed of 20 miles/hour in the first half trip, then 30 miles/hour in one third of the total trip. What is the average speed? ------------------------------------------------------------ 请大家讨论。 ================================== 5、1/3^2*5^2, 2/3^2*5^2, 7/3^3*5^2, 45/3^4*5^5, 75/3^4*5^5 Which one is the largest? It looked like an old JJ. It was my last one when 15 minutes were left. So I was not in a hurry. Not difficult though. ------------------------------------------------------ 7/3^3*5^2 =========================== 6、Some one is planting a plant. The cost of it last year was P, with an amount of N for plants. This year, with the same budget, while the cost increased 25%, how many plants can be planted? ----------------------------------------------------- N/1.25 我的解法： NP/1.25P ========================================================= 7、Some city in 1984. 40% population own computers. In 1990, the population owns computers increased 30% (Which means 40% of P), while the total population(which means the total P in 1984) increased 4%. What is the percentage of population who own computers? --------------------------------------------------- 50% ======================================== 8、A graph like this. The angles in the top half are x, 2x, 2x, 2x, and 3x. How much is y? /\2x 2x/ \2x | |3x | /|y x|/_| ------------------------------------------------ 18 ====================================== 9、DS A big cantainer is letting water go. Is the leaking speed greater than 12 Liters/hour? 1 liter = 1000 ml 1) speed < 2ml/sec 2) speed < 5ml/sec --------------------------------------------- A ==================================================== 10、9 positive intergers. can we find the median? 1) Mean of 4 smallest ones are 150 2) Mean of 4 largest ones are 500 C ------------------------------------------------- 问的可能是what is the median of these 9 positive intergers吧？ 若问能否找出，条件1）、条件2）都能回答：不能。 E ====================================== 11、x^3*y^2*z<0? 1) xyz<0 2) x^2*y>0 C ----------------------------- C ===========================================