SOLUTION: the oldest child in the family of four children is three times as old as the youngest. the two middle children are 21 and 22 years old. if the average age of the children is 27.75,

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Question 829970: the oldest child in the family of four children is three times as old as the youngest. the two middle children are 21 and 22 years old. if the average age of the children is 27.75, how old is the youngest child?
Answer by TimothyLamb(4379) About Me  (Show Source):
You can put this solution on YOUR website!
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x = youngest
y = mid younger
z = mid older
u = oldest
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u = 3x
y = 21
z = 22
(x + y + z + u)/4 = 27.75
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put the system of linear equations into standard form:
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3x - u = 0
y = 21
z = 22
x + y + z + u = 111
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copy and paste the above linear system in standard form into this matrix-method solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
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solution:
x = youngest = 17
y = mid younger = 21
z = mid older = 22
u = oldest = 51
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