SOLUTION: In five years time, Nana's sister will be three times as old as nana. Four years ago, her sister was 6 times as old as her. Find their present ages.

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Question 909155: In five years time, Nana's sister will be three times as old as nana. Four years ago, her sister was 6 times as old as her. Find their present ages.
Answer by clearblueskai(22) About Me  (Show Source):
You can put this solution on YOUR website!
let x = Nana's present age
y = her sister's present age
in five years time:
x+5 = Nana's age
y+5 = her sister's age
y%2B5+=+3%28x%2B5%29
fours years ago:
x-4 = Nana's age
y-4= her sister's age
y-4=6%28x-4%29
Equations:
y%2B5=+3%28x%2B5%29 = y-3x-10=0
y-4=6%28x-4%29 = y-6x%2B20
Elimination:
y-3x-10=0+ -y%2B6x-20= 3x-30=0
x=10
y%2B5=3%2810%2B5%29
y%2B5=30%2B15
y=40
Nana: 10 years old Her sister: 40 years old