24要考了。。。PREP1 三道数学题求助！

StrayLx

做了PREP1 竟然有3道数学题看了答案还想不通。。。

1、Before being simplified, income tax were to add 2 percent of one's annual income to the average of 100 units of country R's currency and 1 percent of one's annual income. annual income is I ,then the formula for tax is:
A.50+I/200   B.50+3I/100  C.50+I/40  D.100+I/50  E.100+3I/100
答案是C。。。完全不懂。。。

2、if x^4+y^4=100, then the greatest possible of value of x is between:
A.0 and 3   B.3 and 6 .......
答案是B，是不是错了？

3、List K consists of 12 consecutive integers. If -4 is the least integer in list K, what is the range of the positive integers in list K?
答案是6，数来数去都是7啊。。。

求助求助啊！谢谢！

richardzi

1. 2%I + (100 + 1%I)/2  => 50 + I/40 => C

2. 3^4 = 81, 4^4 = 256, =>  3<x<4  and this is a subset of (3,6) => B

3. List K = (-4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7) => the range of positive intergers in List K = 7 - 1 = 6

dhqhtn

1. 我觉得你是没看懂题 add a to (the average of a and b) 也就是说
2%I +（100+1%I）/2 就出来了
2. 看清是 最大value 最大value 肯定 大于 3 所以 在3到六之间
3. 看明白球的是 range 范围 所以范围是 7-1 =6
加油！！！

StrayLx

明白了 谢！

StrayLx

的确是没看懂题啊。。。你一说就明白了！谢！