Question 1053655: In two years bob will be three times as old as Al. 8 years ago, Bob was 5 times his age. How old is bob now? Answer by addingup(3677) (Show Source):
You can put this solution on YOUR website! I just answered this question:
Let Bob be b and Al A.
b+2 = 3(a+2) = 3a+6
b = 3a+4
b-8 = 5(a-8)
b-8 = 5a-40 substitute for b:
3a+4-8 = 5a-40
3a-4 = 5a-40
36 = 2a
flip it:
2a = 36
a = 18 Al is 18
b = 3a+4 = 3(18)+4 = 54+4 = 58 Bob is 58
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Check:
In 2 years Bob will be 3* older than Al
58+2 = 60 and 18+2 = 20 and 20*3 = 60 Correct
and
8 years ago Bob was 5 times Al
58-8 = 5(18-8) = 50 = 5*10 Correct
