Question 346209
Hi,
*Note: Fred "will be and always was" 4 years older than Barney
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Let f be Freds age and b be Barneys's age "five years ago"
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the question states the following to be true:

f + b = 48 substitute for fred's age (b + 4)
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(b + 4) + b = 48  
2b = 44
b= 11  Barney's age five years ago.
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Barney is NOW 16 and Fred 20