请教两道PREP的数学题，谢谢先

anchoretes

175.


Before being simplified, the instructions for computing income tax in Country R were to add 2 percent of one's annual income to the average (arithmetic mean) of 100 units of Country R's currency and 1 percent of one's annual income.Which of the following represents the simplified formula for computing the income tax, in Country R's currency, for a person in that country whose annual income is I ?



(A)50 + (I/200)

(B)50 + (3I/100)

(C)50 + (I/40)

(D)100+ (I/50)

(E)100+ (3I/100)

答案C，不知道如何做



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178.
If there are more than two numbers in a certain list, is each of the numbers in the list equal to 0 ?



(1)The product of any two numbers in the list is equal to 0.



(2)The sum of any two numbers in the list is equal to 0.

【答案】B



破解里的【思路】(1)任何數相乘只要數列有一個0,乘積為0,但不代表數列均為0,不充份

(2)任何數相加為0,其必為兩個0,充份

但我认为选D，对于条件1，如果一个LIST里有三个数，3，5，0---那么3和0，5和0的积是0，没错，但3和5的积就不是0了，与The product of any two numbers
矛盾，所以还得都是0，对吗？



请NN帮忙看看，多谢啦……

shlshing

第二题，A不对，比如存在。0，3，0的情况，任何两个乘积就都是0了~

anchoretes

好的，谢谢楼上！

哪位大侠帮忙解下第一题啊？感激不尽！

banglixing

add 2 percent of one's annual income to the average (arithmetic mean) of 100 units of Country R's currency and 1 percent of one's annual income.  意思是 0.02I + (100+0.01I)/2 = 50+0.025I

anchoretes

多谢楼上，还是英语问题呀~