Question 775854: X was twice as old as Y 10 years back. how old is Y if X will be 45 years old 15 years hence ?
Found 2 solutions by psbhowmick, MathTherapy:
Answer by psbhowmick(878)   (Show Source):
You can put this solution on YOUR website! Let X be x years old and Y be y years old now.
10 years back:
X was (x - 10) yrs old
Y was (y - 10) yrs old
At that time X was twice as old as Y.
x - 10 = 2(y - 10)
x = 2y - 20 + 10
x = 2y - 10 ___________ (i)
After 15 yrs from now, Y's age would be (y+15) yrs.
Given that after 15 yrs from now Y will be 45 yrs old.
y + 15 = 45
y = 45 - 15 = 30 ___________ (ii)
Substituting the value of y from (ii) in (i)
x = 2*30 - 10 = 50
So now X is 50 yrs old and Y is 30 yrs old.
Answer by MathTherapy(10551)  (Show Source):
You can put this solution on YOUR website!
X was twice as old as Y 10 years back. how old is Y if X will be 45 years old 15 years hence ?
Let xs current age be x, and ys, y
Then 10 years ago, x was x 10, and y was y 10
Therefore, x 10 = 2(y 10), or x 2y = - 10 ---- eq (i)
Since 15 years from now, x will be 45, then x is now 30 (45 - 15)
30 2y = - 10 ------ Substituting 30 for x in eq (i)
2y = - 10 30
- 2y = - 40
Y is currently  , or  years-old
You can do the check!!
Further help is available, online or in-person, for a fee, obviously. Send comments, thank-yous, and inquiries to D at MathMadEzy@aol.com
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