这几天陆续回忆了一些 2/16 的 Math，希望对大家有帮助 1. If we know X^2 = X+1, what is X^ 3? A: 2X+1 2. 一个数列，median是x，最大数是15，range比median大8，求最小数。 A：7－x
3. 那道倒置的等腰梯形容器：一个等腰梯形形状的容器，倒着放，上面两个角都是45度，上底是1.5m ，下底是0.5m，高是2m，
然后说一立方米可以容纳1000kg的水，后来说这个容器里面最后装了750kg的水，问装了水的部分的高是多少？（数据是应该对） 注意
注意 注意 1). 原题给出倒梯形简图，只标出45度，好像尺寸未标出 2). 答案选项以分数形式给出
e.g. 2/3, 3/2, 4/3, 3/4 4. DS: S and T are 2 sequences, both have same number of positive integers, is the media of S > the mean of T? 1) sum of S > sum of T 2) S is consecutive of even numbers, and T is consecutive of odd numbers. 5. DS: Is x/3+3/x>2? 1) x<2 2) x>1 6. DS: -1<X<1, is Y>X^2? 1) Y>X 2) Y>0 8. A group of people form an array of 60 * 80. What is the diagonal distance? A: 100 9. 450 seats in a theatre, each row has same number of seats. Increase the number of seat by 3 per row, can reduce 5 row of seats. Ask what is number of seats per row? 10. A book of 360 pages, start reading from Sunday, and finish all the pages on the following Friday. Each day read additional 10 pages. How many pages do you read on Sunday? 11. If X is divided by 5, remainder is 1; if x is divided by 7, remainder is 3. X+Y is divisible of 35. What is minimum of Y? A: Y=4 12. DS: A sequence of K positive integers, what is the sum of the remainders divided by 7? 1) K>0 2) K=7 13. DS Tom is working, his pay (P) structure is simplified according to how many hours he worked each week: P=$300 (work T<10 hour) P=$200+$10 * T (work 11<=T<20 hours) P=$20*T (work T>=20 hours) Ask, how many hour did he work on 2nd week? 1) he work 2 more hours on 2nd week than 1st week; 2) he get $20 more than for on 2nd week than 1st week; (数据基本正确) 14. DS Somebody invested in 2 funds. This year, the first fund (F1) increased by 6%, take 30%; the second fund (F2) increased by 7.2%. Now, this invester wants to take out 30% of first fund and 35% of the second fund. Is the amount of money he took out from the first fund bigger than the one from the second fund? 1) Initially, he invested $12000k in the first fund. (F1=12000k) 2) Initially, he invested in F2= F1*0.85; 15. 一个长方形ABCD，上边长AD上有点E，下边长BC上有点F，其中BF:CF是4：3；长方形面积是84，求三角形BEF的面积。 A: 24 16. 27,135 (10^12-10^11)/10^13, what is the units? 17. The ultimate digit number for 999939 is 9+9+9+9+3=39 => 3+9=12 => 1+2=3; how many 2 digit number will have the ultimate number of 2? A: 10 18. A team is building river bank, 24 worksor, 30 hours, to complete 15 meters; now in order to build 6 meters long 25 workers, how many hours will it take? (number given here can be wrong) 19. DS: [x] is to calculate the integer that is equal or least bigger than x. [w/3]=4 1) w<12 2) w>10 20. Positive integer X and Y. If X is divided by 15, remainder is 1; if X+Y is divided by 15, remainder is 1. What is min of Y? A: 14; X=15b+1 X+Y = 15c+1 Y =15 (c-b)-1, b>=1, c>=2, c-b>=1, =>Y>=14; 又想起来一题 21. A, B, C work on the project. A finished the first quarter (1/4) of the project in 2 hours. Then B and C join. It will take 3 persons 3 hours to complete the rest of the project. If only C work on the rest project (3/4) alone, he will take 18 hours. How many hours will B use if he works alone for this whole project? A: 12 hours. (1/4)/2+1/B+(3/4)/18 = (3/4) /3 => B=12 | 
