Question 1093791
a = 2b-8
c = b+4
and 
a+b+c = 60
substitute with the values above:
2b-8+b+4+b = 60
4b-4 = 60
4b = 64
b = 16
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So now we have that: 
b = 16
a = 2b-8 = 2(16)-8 = 24
c = b+4 = 16+4 = 20
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Check:
24+16+20 = 60 Correct