Question

SAT数学问题

1.a salesperson's commission is k percent of the selling price of a car . Whick of the follwing represents the commission ,in dollars ,on 2 cars that sold for $14,000 each
为什么（A)280K 是对的 （C)28,000K是错的
2.The first term of a sequence of numbers is 1.if each term after the first is the product of -2 and the preceding term,what is the sixth term of the sequence帮我翻译一下这个问题

Answer 1

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