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The average of Amy's, Ben's, and Chris's ages is 9. Four years ago, Chris was the same age as Amy is now. In 3 years, Ben's age will be 2/3 of Amy's age at that time. How many years old is Chris now?

 Mar 16, 2020
edited by Guest  Mar 16, 2020
edited by Guest  Mar 16, 2020
 #1
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(a + b + c )/3 = 9

 

c-4 = a    c = a+4

b+3       = 2/3 ( a +3)        b = 2/3( a+3)  - 3       Sub the red in to the top equation

 

(a + 2/3(a+3)-3   +   a+4 )/3 = 9

2  2/3 a   +3 = 27

8/3 a = 24

a = 9               then   c=a+4 = 13  y/o                 and b=5

 Mar 16, 2020
edited by ElectricPavlov  Mar 16, 2020
 #2
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ok i put the part in

Guest Mar 16, 2020

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