Find the minimum integer

rongya

(a+b/c).(e+d) where a, b,c,d,e are distinct integer from 1-9. What is the minimum integer answer we have from the equation above. And Justify your answer by proof why there is no smaller integer answer.

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Yalong

一群大笨蛋,就楼主聪明!但要琢磨楼主的英文,恐怕８０秒还不够. www.ddhw.com

rongya

Finally, you got the right answer. But you know what the average time to do this question is only 80 seconds.

ob

  

yinyin

(1+3/9)*(2+4)=8. www.ddhw.com

ob

(4+3/9)*(1+2)=13 (3+4/6)*(1+2)=11 (2+4/8)*(1+3)=10 (1+4/5)*(2+3)=9 Seems 9 is the minimum integer.

开开心心

(2+4/8)*(1+3) =10 www.ddhw.com

yinyin

Sorry for my misunderstanding! If the dot in the expression is the multiplication operator, then the minimun value of the expression is 15, which is reached by (1+8/4)*(2+3) or (3+8/4)*(1+2).

rongya

I think you made a mistake in understanding of this question. The question is (a +b/c), it is not (a+b)/c. So the answer is not 3. www.ddhw.com

yinyin

The reason for the answer being 3 is: (a+b)*(d+e) is at least 21. If it can be exactly divided by an integer between 1 and 9, the quotient is at least 3. www.ddhw.com

yinyin

Welcome! To clarify the problem, I suggest rewriting it as: "Consider (a+b/c)*(e+d) where a, b,c,d,e are distinct integers from 1-9. What is the minimum integer value we can obtain from the expression above? In addition, justify your answer by showing why there is no smaller integer answer. " If my suggestion is correct, the answer should be 3 with (1) a+b = 4, c=8, and e+d = 6; or (2) a+b = 3, c=9, and e+d = 9; or (3) a+b = 3, c=7, and e+d = 7; or ...... www.ddhw.com     本贴由[yinyin]最后编辑于：2007-5-30 2:51:36