1.k percent = 百分之k = k/100
“2 cars that sold for $14,000 each”的selling price=28000.
因此这个salesperson的commission=28000×(k/100)=280k
2.“The first term of a sequence of numbers is 1”：一个数列的第一项等于1.
“if each term after the first is the product of -2 and the preceding term”：每下一项等于上一项乘以（-2）.
“what is the sixth term of the sequence”：问第六项是什么?
第一项是1,
我们可以得到第二项等于1×（-2）=-2
第三项=-2×-2=4
以此类推.
总之这个是等比数列,公比为-2,第一项为1,那么第六项就是(-2)^5=-32