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Amy is 9 years older than her younger sister. if her younger sister is now 1 year old, how many years later will Amy be 4 times as old as her younger sister?​

User Peterc
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1 Answer

4 votes

Answer:-

  • Age of Amy's younger sister=1year

Amy is 9 years older than her younger sister.


\\ \sf\longmapsto Age\:of\:Amy=1+9=10years

Let after x years Amy will be 4times old as her sister.

ATQ


\\ \sf\longmapsto (1+x)/(9+x)=(1)/(4)

  • Using cross multiplication


\\ \sf\longmapsto 4(1+x)=1(9+x)


\\ \sf\longmapsto 4+4x=9+x


\\ \sf\longmapsto 4x-x=9-4


\\ \sf\longmapsto 3x=5


\\ \sf\longmapsto x=(5)/(3)


\\ \sf\longmapsto x=1.6


\\ \sf\longmapsto x=2(approx)

User Ed Norris
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