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The product of Shikha’s age five years ago and her age 8 years later is 30, her age at both times being given in years. Find her present age.
Given:
The product of Shikha’s age five years ago and her age 8 years later is 30, her age at both times being given in years.
To do:
We have to find her present age.
Solution:
Let the present age of Shikha be $x$ years.
This implies, the age of Shikha 5 years ago$=x-5$ years.
The age of Shikha 8 years later$=x+8$ years.
According to the question,
$(x-5)(x+8)=30$
$x^2-5x+8x-40=30$
$x^2+3x-40-30=0$
$x^2+3x-70=0$
Solving for $x$ by factorization method, we get,
$x^2+10x-7x-70=0$
$x(x+10)-7(x+10)=0$
$(x+10)(x-7)=0$
$x+10=0$ or $x-7=0$
$x=-10$ or $x=7$
Age cannot be negative. Therefore, the value of $x$ is $7$.
The present age of Shikha is $7$ years.
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