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 ?


Let x’s current age be x, and y’s, 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 {{{(- 40)/- 2}}}, or {{{highlight_green(20)}}} years-old


You can do the check!! 


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