HMMT 二月 2000 · GEN 赛 · 第 9 题
HMMT February 2000 — GEN Round — Problem 9
题目详情
- Edw ard's form ula for the sto k mark et predi ts orre tly that the pri e of HMMT is dire tly prop ortional to a se ret quan tit y x and in v ersely prop ortional to y , the n um b er of hours he slept the nigh t b efore. If the pri e of HMMT is $12 when x = 8 and y = 4, ho w man y dollars do es it ost when x = 4 and y = 8?
解析
- Let p b e the pri e of HMMT. So p = k , where k is a onstan t to b e determined. W e y kno w that when x = 8 and y = 4 that p = 12, so, solving for k , w e nd that k = 6. So, 4 when x = 4 and y = 8, w e nd that p = 6 = 3 . 8