SOLUTION: A girl is twice as old as her sister .four years hence,the product of their ages will be 160.find their present ages

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Question 280277: A girl is twice as old as her sister .four years hence,the product of their ages will be 160.find their present ages
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
g=2s
(g+4)*(s+4)=160
(2s+4)*(s+4)=160
2s^2+4s+8s+16=160
2s^2+12s+16=160
2s^2+12s-144
s^2+6s-72=0
(s-6)*(s+12)=0
s=6
g=2s
g=12
check
10*16=160
ok