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The sum of five different positive integers is 320. The sum of the greatest three integers in this set is 283. The sum of the greatest and least integers is 119. If x is the greatest integer in the set, what is the positive difference between the greatest possible value and least possible value for x?

wiskdls  Mar 17, 2018
 #1
avatar+86861 
+2

I'm using  "e" for  "x"

 

Let   a < b < c < d < e

 

So we have......

 

a + b + c + d + e  = 320   (1)   

Where "a" is the smallest integer and "e" is the largest

And

c + d + e  =  283    (2)  

a + e  = 119     (3)

 

Sub (2) into (1)

a + b + 283  =  320

a + b  =  37

 

Let  a  =  1

Then.....as large as "e" can be is

1 + e  = 119

e  = 118

 

 

Let  a  = 36

Then......  a possibility for as small as "e" can be  is

36 + e  = 119

e  = 83

 

However     c < d < e

And  c + d + e  = 283

So....e will be minimized when  the sum of c and d are as large as possible

If      c  = d = e = 95

95 * 3  =  285....but  c and d  are < e.....so....c and d < 95  and  c < d

So....the largest that the sum of c and d can be  is  93 + 94  =   187

But.....

93 + 94 + 95   =  282   ......too small

Then e cannot be < 96  because  93 + 94 + 96  = 283

 

So.....as  small as e  can be  is  96   and as large as e can be  is  118

 

So.....the positive difference   between  the greatest positive value of  e   and the least positive value of e  is   118 - 96   =  22

 

 

cool cool cool

CPhill  Mar 18, 2018

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