The ratios of ages of A and B is $13:15$. After 9 years, the ratio will be $20:23$. What is the difference in years between ages?


Given: The ratios of ages of A and B is $13:15$. After 9 years, the ratio will be $20:23$.

To do: To find the difference in years between ages.

Solution: 

$\because $ Ratio of ages of A and B $=13:15$ 

Let $13x$ and $15x$ are the ages of A and B respectively.

After $9$ years:

Age of A $=13x+9$

Age of B $=15x+9$

As given, 

After $9$ years ratio of the ages of A and B is:

$( 13x+9):( 15x+9)=20:23$

$\Rightarrow \frac{13x+9}{15x+9}=\frac{20}{23}$

$\Rightarrow 23( 13x+9)=20( 15x+9)$

$\Rightarrow 299x+207=300x+180$

$\Rightarrow 300x-299x=207-180$

$\Rightarrow  x=27$

$\therefore$ Age of A $=13x=13\times27=351$ 

Similarly Age of B $=15x=15\times27=405$

Difference between their ages  $405-351=54$ years

Updated on: 10-Oct-2022

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