Question

a girl is twice as old as her sister 5 yrs hence is the product of their age will be 160 find there present age

Answer 1

Please see the attachment. then answer is in it.

f70c5583ecd0165400cc9fa6780465de.pdf

Answer 2

solution :
     First of all , there is a mistake in your question , the question should be ..
A girl is twice as old as her sister 5 yrs hence  the product of their age will be 160 find their present age?               let Present age of Girl's Sister (in Years) = x
                    therefore , Girl's Present  age (in Years) = 2x
                     Five years later ,
                                 Girls Sisters Age = x+5
                                 Girls age = 2x+5
                     According to question ,
                             (x+5)(2x+5)=160
                             x(2x+5)+5(2x+5)=160
                             2x² + 5x +10x +25 =160
                             2x² +15x + 25 =160
                             2x² +15x + 25 -160 =0
                             2x² +15x  -135 =0
Solve the Quadratic Equation ,
                     here a=2
                             b=15
                             c=-135
                   D=-b+√b²-4ac/2a
                   D= -15+√15² - 4 *2*(-135)/2*2
                       =-15+√225 +1080/4
                       =-15+√1305/4
                       =-15+36.12/4
                       = 21.12/4
                       =5.28


  HENCE pRESENT AGE OF Girls Sister = 5.28 Years
     and the Present Age of Girl = 2*5.28
                                                 =10.56 Years

Hope This Helps You!!

Thank You !!

Cheers!!!