SOLUTION: Mr. Smith is 5 times as old as hiandsons gr. Four years ago, he was 7 times as old as his grandson. How old is he?

Question 979578: Mr. Smith is 5 times as old as hiandsons gr. Four years ago, he was 7 times as old as his grandson. How old is he?
Answer by Cromlix(4381) (Show Source): You can put this solution on YOUR website!
Hi there,
Mr. Smith is 5 times as old as his grandson.
S = 5G
........
Four years ago, he was 7 times as old as his grandson.
S - 4 = 7(G - 4)
Multiply out
S - 4 = 7G - 28
Replace 'S' with '5G'
from top equation
5G - 4 = 7G - 28
collect like terms
5G - 7G = - 28 + 4
-2G = -24
Multiply both sides by -1
2G = 24
G = 12
Mr Smith is (12 x 5) 60 years old
Grandson is 12 years old.
Hope this helps:-)

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