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Mrs.Santos is 20 years older than her daughter.In 5 years,she will be 5 years more than twice as old as her daughter.Find their present age.

 Jun 2, 2020
 #1
avatar+25460 
+1

Mrs.Santos is 20 years older than her daughter.
In 5 years,she will be 5 years more than twice as old as her daughter.
Find their present age.

 

x is Mrs.Santos

y is her daughter

 

\(\begin{array}{|lrcll|} \hline (1) & \mathbf{x} &=& \mathbf{ y +20} \\\\ (2) & \mathbf{x+5} &=& \mathbf{2(y+5)+5} \quad | \quad x=y+20 \\ & y+20+5 &=& 2(y+5)+5 \\ & y+25 &=& 2y+10+5 \\ & y+25 &=& 2y+15 \\ & 25-15 &=& 2y-y \\ & \mathbf{10} &=& \mathbf{y} \\\\ (1) & x &=& y +20 \\ & x &=& 10 +20 \\ & \mathbf{x} &=& \mathbf{30} \\ \hline \end{array}\)

 

She is 30 years old and her daughter is 10 years old.

 

laugh

 Jun 2, 2020
 #2
avatar+25820 
+1

S = D +20           and in 5 years:

S+5 = 2(D +5) +5     or    S = 2D+10    Sub into first equation

 

2D+10 = D +20

D = 10             then     S = 30  

 Jun 2, 2020

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