Question

The product of raju's age 5years ago and his age 10years later is 16 determine Raju's present age

Answer 1

let presant age of raju  be = x
before 5 years,raje age = x-5
later 10 year,Raju age will be= X+10
According to situation
(X-5)(X+10)=16
x^2+10x-5x-50=16
x^2 +5x-66=0
x^2+11x-6x-66=0
x(x+11)-6(x+11)=0
(x+11)(x-6)=0
x=-11,6
We neglect x=-11 ,because age never be negative
Hence Raju age at present will be 6 year

Answer 2

Let Raju's  age 5yrs ago be = x
10yrs letter his age will be= x+5+10 = x+15
As per question x(x+15)=16
                     ⇒  x²+15x-16=0
                     ⇒ x² +16x -x-16 =0
                     ⇒ x(x+16) -(x+16)=0
                     ⇒ (x+16)(x-1)=0
                     ⇒ x= -16 or 1 we neglect -16
                     Hence x=1
Raju's present age= x+5=1+5=6