数学和英语好的进来啊不过不用每题都写出来,大概的思路就够了,,都答对,而且过程清楚（中文就行）有加分的,7.Ninetimesthesumofanumberandfourteenisthreemorethantentimesthediferencewhenthenumber

Question

数学和英语好的进来啊
不过不用每题都写出来,大概的思路就够了,,都答对,而且过程清楚（中文就行）有加分的,
7.Nine times the sum of a number and fourteen is three more than ten times the diference when the number is subtracted from fifty-six.Find the number.
10.Tom and Brenda each have a whole number of dollars.Four fifths of Tom’s money is equal to five sevenths of Brenda’s money.If Tom and Brenda each have less than $50,
how much do they have together?
9.If you add 1/4 of the price of a candy bar to 1/2 of the change you would get if you bought the candy bar with a dollar (no tax),you get the exact price of the candy bar.How
much is the candy bar?
11.Let’s agree that a number with three of the same digits in a row will be called a triplet.Let’s also agree that a number with four of the same digits in a row will be called a quadruplet and cannot be counted as a triplet.How many triplets are there between 1000 and 2000 (excluding 1000 and 2000)?
13.The “proper” factors of a number are all the factors except the number itself.Find the sum of the numbers between 20 and 30 for which the product of the proper factors of the
number equals the number itself.

Answer 1

7.9乘以一个数与14的和比10乘以这个数与56的差多3,求这个数
设这个数为x,9(x+14)=10(x-56)+3,解得x=431
10
汤姆和布兰德每人有若干美元,汤姆钱的4/5和布兰德的5/7一样多,每个人的钱不超过50美元,他们一共多少钱?
设每人有x,y美元,x,y是整数
4/5x=5/7y
也就是28x=25y
因为(25,28)=1,所以x=25,y=28是50以内的唯一一解
汤姆有25美元,布兰德有28美元,一共有25+28=53美元
9.有一个块状糖,如果你把它价格的1/4加上用1美元去买这个糖找零的1/2和它原来的价格一样,这个糖的价格是多少?
设这个汤的价格是x
x/4+1/2(1-x)=x
解得x=2/5,原来那颗糖2/5美元
11.定义包含三个相邻同样数字的数为一个三元组.定义包含四个相邻同样数字的数为4元组(不能被当做三元组),那么1000-2000之间有多少3元祖和3元组(不包括1000和2000)?
举例来说,1222是三元组,2222是四元组但不是三元组
1000-2000之间三元组有17个:
1222,1333,1444,1555,1666,1777,1888,1999,1110,1112,1113,1114,1115,1116,1117,1118,1119
四元组只有一个:
1111
12定义一个整数的"非平凡"因数是不包括它本身的所有因数.找出20-30之间所有非平凡因数的乘积等于他本身的数
一个个试:
20因数1,2,4,5,10,积>20
21因数1,3,7,积=21,OK!
22因数1,2,11,积=22,OK!
23因数1,积=1
24因数1,2,3,4,6,8,12,积>24
25因数1,5,积=5
26因数1,2,13,积=26,OK!
27因数1,3,9,积=27,OK!
28因数1,2,4,7,14,积>28
29因数1,积=1
30因数1,2,3,5,6,10,15,积>30
所以满足条件的数共有4个,21,22,26,27