SOLUTION: Jack is 15 years old, and his sister, Jane is 5 years old. In how many years will jack be twice as old as Jane?

Question 137173: Jack is 15 years old, and his sister, Jane is 5 years old. In how many years will jack be twice as old as Jane?
Found 2 solutions by ankor@dixie-net.com, checkley77:
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Jack is 15 years old, and his sister, Jane is 5 years old. In how many years will jack be twice as old as Jane?
:
You can do this in your head but here is the algebra way.
:
Let x = no. of years for this to happen
:
15 + x = 2(5+x)
:
15 + x = 10 + 2x
:
15 - 10 = 2x - x
:
5 = x; In five yrs Jack will be 20 and Jane will be 10

Answer by checkley77(12844) (Show Source): You can put this solution on YOUR website!
Jack=15
Jane=5
15+x=2(5+x)
15+x=10+2x
x-2x=10-15
-x=-5
x=5 years from now Jack will be twice as old as Jane.
proof:
15+5=2(5+5)
20=2*10
20=20

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