Question

The product of shankar's age 5 yrs ago and his age 8yrs later is 30 his ages at both time being given in years what is his persent age?

Answer 1

$<b><font face=Copper black size=4 colour=purple>$$<b><marquee direction = "up" > <h3>$Let,

Shankar's age = x yrs

Now,

5 yrs ago,

Shankar's age = ( x - 5 ) yrs

8 yrs later,

Shankar's age = ( x + 8 ) yrs

A/q

( x - 5 ) ( x + 8 ) = 30

x ( x + 8 ) - 5 ( x + 8 ) = 30

x² + 8x - 5x - 40 = 30

x² + 3x - 70 = 0

x² + 10x - 7x - 70 = 0

x ( x + 10 ) - 7 ( x + 10 ) = 0

( x + 10 ) = 0 and ( x - 7 ) = 0

x = - 10 and x = 7

Shankar's age = 7 yrs

[ Neglecting - ve value i.e. x ≠ - 10 ]

^^"

Answer 2

Let us consider Shankar's present age be x years
So Shankar's age 5 years ago will be x-5
And his age 8 years later will be x+8
According to the given condition
x-5 *x+8 =30
x2 +8x-5x-40=30
x2 +3x-40-30=0
x2+3x-70=0
x2+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
x is not equal to-10 since age cannot be negative
x=7
Shankar's present age is 7 years