Question 681040: Lisa will be twice as old as her brother Ralph in 6 years. Lisa was three times as old as Ralph 3 years ago. What are their ages now? Answer by htmentor(1343) (Show Source):
You can put this solution on YOUR website! Lisa will be twice as old as her brother Ralph in 6 years. Lisa was three times as old as Ralph 3 years ago. What are their ages now?
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Let L = Lisa's current age
Let R = Ralph's current age
In 6 years Lisa will be twice her brother's age:
L+6 = 2(R+6)
L = 2R + 12 - 6
L = 2R + 6
3 years ago Lisa was 3 times her brother's age:
L-3 = 3(R-3)
(2R+6)-3 = 3R - 9
This gives R = 12
So Ralph is 12 yrs old and Lisa is 2*12 + 6 = 30 yrs old
