Question

英语数学题

各位大虾!!!大家有英语数学题吗?????我跪求!!!
最好是网站!!!!而且是小学的!!!!

Answer 1

1.The sum of n different natural numbers is less than50.the greatest possible value of n is----
2.Let a be the average of all odd prime numbers less than 50.The inreger,most close to a is----
3.If two even natural numbers x,y satisfy equation x
答案：
1. Since there are some controversies, I suppose 0 does not belong to natural numbers in this case. The answer is quite straight foward, 1+2+3+4+5+6+7+8+9=45. If we add 10, then the sum will exceed 50. So the greatest possible n is 9.

2. First of all, you can list all the odd prime numbers less than 50:3 5 7 11 13 17 19 23 29 31 37 41 43 47. Add them up, and calculate the average. The average a is equal to 23.3. Therefore the integer, most close to a is 23.

3. x^2+100=y^2,then (y-x)(x+y)=100, since x and y are natural numbers, x+y>0, y should be larger than x. I am afraid there is either something wrong with the problem or a typing mistake.
You can show me the original version of the problem 3.

Answer 2

1.There are three options in which a company can hire a copier machine.
Scheme A : basic charge of $650 a month with unlimited copies .
Scheme B : basic charge of $200 a month and $0.015 for each photocopy.
Scheme C : basic charge of $100 a month and $0.02 for each photocopy.

Calculate the break even quantity between each scheme and hence, advice the company on the 3 options.
2.eight cards are selected with replacement from a standard pack of 52palying cards,with 12 picture cards ,20 odd cards and 20 even cards.
Q: how many of the sequence will contain three picture cards ,three odd-numbered cards and two even-numbered cards
3.Let U be a set containing 29 objects and let S1,S2,S3,...,S10 be 10 subsets of U, not necessarily distinct. Suppose that every 5 of the subsets taken together contain all 29 objects of U. Show that some three of these subsets taken together contain all 29 objects of U.
4.Thirteen less than twice a number is seventeen more that half the number. what is the number?
5.For-a-real-number-a,let[a]denote-the maximum-integer-which-does-not-exceed-a.For example,[3.1]=3,[-1.5]=-2,[0.7]=0.Now let
.....x+1
f(x)=—
.....x-1,then[f(2)]+[f(3)]+L+[f(100)]
(real-number:实数,the maximum-integer-which-does-not-exceed-a:不超过a的最大整数)

Answer 3

1.The sum of n different natural numbers is less than50.the greatest possible value of n is----
2.Let a be the average of all odd prime numbers less than 50.The inreger,most close to a is----
3.If two even natural numbers x,y satisfy equation x的平方加100等于y的平方,x大于y then x乘y等于----

Answer 4

让所有的奇素数的平均数小于100的整数。，最接近的是（）