XDF蓝皮题目求解

hlnbisheng

蓝皮133页第7题，和147页94题

7。in the expression above,a,b,and c are differerent numbers and each is one of the numbers of 2,3or 5.what is the least possible value of the expression?(a/b)/c

A 1/30 B2/15 C 1/6 D 3/10E5/6

 94. what is the least possible product of 4 different integers, each of which has a value between -5 and 10,inclusive?

A.-5040  B-3600 C-720 D-600 E -120

fons

7.答案应该是B吧

因为要使表达式最小 所以C要尽可能大 取5 同时B也要取大值 取3 答案就出来了

 

94.答案也是B吧

求最小值，那就是要尽可能靠近负无穷大。然后该最小值的绝对值要尽可能大，所以取正数里面绝对值最大的三个 8 9 10 然后去一个负数 绝对值也要大 那就是-5 答案也就出来了！