SOLUTION: Isaac is nine years older than Kylie. Isaac is four times as old as Brian was three years ago. Brian is eighteen years younger than Isaac. How old is Kylie?
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Question 157768: Isaac is nine years older than Kylie. Isaac is four times as old as Brian was three years ago. Brian is eighteen years younger than Isaac. How old is Kylie? Answer by nerdybill(7384) (Show Source):
You can put this solution on YOUR website! Isaac is nine years older than Kylie. Isaac is four times as old as Brian was three years ago. Brian is eighteen years younger than Isaac. How old is Kylie?
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Let k = Kylie's age
from:"Isaac is nine years older than Kylie." we get
k+9 = Issac's age
from:"Brian is eighteen years younger than Isaac."
k-18 = Brian's age
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Our equation is derived from:
"Isaac is four times as old as Brian was three years ago."
(k+9) = 4[(k-18)-3]
k+9 = 4[k-18-3]
k+9 = 4[k-21]
k+9 = 4k-84
9 = 3k-84
93 = 3k
31 years = k (Kylie's age)
