SOLUTION: Last year,Grok's mother weighed 3 times as much as Grok. Since then Grok has gained 9 kg and his mother has lost 4 kg. Now his mother weighs only twice as much as Grok. Find their

Question 363859: Last year,Grok's mother weighed 3 times as much as Grok. Since then Grok has gained 9 kg and his mother has lost 4 kg. Now his mother weighs only twice as much as Grok. Find their weights now.
Answer by amoresroy(361) (Show Source): You can put this solution on YOUR website!
Let g = weight of Grok last year in kg
m = weight of Grok's mother last year in kg
m = 3g
m-4 = 2(g+9)

since m = 3g
(3g)-4 = 2(g+9)
3g -4 = 2g + 18
3g-2g = 18+4
g = 22

m = 3*22
= 66

Note that:
g+9 = weight of Grok now
m-4 = weight of Grok's mother now
Grok weighs 31 Kg now
Grok's mother weighs 62 Kg now
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