SOLUTION: Luanne’s age is half the sum of her brothers age and 6. If Luanne is 9 years old, how old is her brother

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Question 1144302: Luanne’s age is half the sum of her brothers age and 6. If Luanne is 9 years old, how old is her brother
Found 2 solutions by greenestamps, ikleyn:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Carefully convert the given information into algebraic expressions.

The number you are looking for is her brother's age; let that be the variable x.
x = brother's age

"the sum of her brother's age and 6": x+6

"half the sum of her brother's age and 6": (x+6)/2

Her age (9) is half the sum of her brother's age and 6:

9+=+%28x%2B6%29%2F2

Solve using basic algebra.

Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.
Luanne’s age is half the sum of her highlight%28cross%28brothers%29%29 brother's age and 6.
If Luanne is 9 years old, how old is her brother
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From the condition, we are given that


         a)  Luanne’s age is half the sum of her brothers age and 6

    and

         b)  Luanne is 9 years old.


It means that "half the sum of her brother age and 6" is 9.


Hence, the sum of her brother age and 6 is 9*2 = 18.


It implies that her brother age is 18-6 = 12.


ANSWER.  Her brother's age is 12 years.


CHECK.   %2812%2B6%29%2F2 = 18%2F2 = 9.   ! Correct !


You may solve the problem by any way: using equations or using logical reasoning.

The movement of your thoughts is the same in both cases.