SOLUTION: Abbey is 3 years younger than Arnold. In four years, Abbey will be exactly half of Andrew's age. The sum of their ages is 63. How old is Abbey?

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Question 1096050: Abbey is 3 years younger than Arnold. In four years, Abbey will be exactly half of Andrew's age. The sum of their ages is 63. How old is Abbey?
Found 2 solutions by greenestamps, josgarithmetic:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!

We have several choices for how to set up the variables and expressions for this problem.

(1) Since the problem asks for Abbey's age, let's let our "primary" variable represent Abbey's age.

(2) Then we will use the given information to find expressions for Andrew's and Arnold's ages in terms of that variable.

(3) When we have expressions for all the ages in terms of a single variable, we will be able to solve the equation that says the sum of those ages is 63.

(1) let B = Abbey's age
let R = Arnold's age
let N = Andrew's age

(2) Then...

Abbey is 3 years younger than Arnold:
B+=+R-3 so R+=+B%2B3

In four years, Abbey will be exactly half of Andrew's age:
B%2B4+=+%28N%2B4%29%2F2%29
2B%2B8+=+N%2B4
N+=+2B%2B4

(3)B+%2B+%28B%2B3%29+%2B+%282B%2B4%29+=+63
4B%2B7+=+63
4B+=+56
B+=+14

Abbey is 14.

Check...:
B = 14, so R = B+3 = 17, and N = 2B+4 = 32.

14+17+32 = 63 yep!

Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
x, Abbey
y, Arnold
z, Andrew

system%28x=y-3%2Cx%2B4=%28z%2B4%29%2F2%2Cx%2By%2Bz=63%29

Look at second equation and first equation:
system%28y=x%2B3%2C2x%2B8-4=z%29
-
system%28y=x%2B3%2Cz=2x%2B4%29


substitute for y and z into the "63" equation:
x%2Bx%2B3%2B2x%2B4=63
-
4x%2B7=63
4x=56
x=56%2F4=%2828%2A2%29%2F4=%284%2A7%2A2%29%2F4
highlight%28x=14%29------------Abbey's age now.