Question

please solve (v) question.....

Answer 1

Let the age of Jacob after 5 year be a

Jacob's father's age after 5 year = 3a

Five years ago,

Jacob's age = (a - 10) year

Jacob's father's age = (3a - 10) year

According to question,

3a - 10 = 7(a-10)

=> 3a - 10 = 7a - 70

=> - 10 + 70 = 7a - 3a

=> 4a = 60

=> a = 15

Jacob's present age = a - 5

= 15 - 5

= 10 year

Jacob's father's present age = 3a - 5

= 45 - 5

= 40 year

Answer 2

Let the fraction be x/y
   (x+2)/(y+2) = 9/11
   (x+2)*11 = (y+2)*9
   11x+22 = 9y+18
   11x-9y = 18-22
   11x-9y = -4          ....(i)

   (x+3)/(y+3) = 5/6
   (x+3)*6 = (y+3)*5
   6x+18 = 5y+15
   6x-5y =15-18
   6x-5y = -3            ....(ii)

   (11x-9y = -4)*5        ....(i)
   (6x-5y = -3)*9          ....(ii)

Subtracting (ii) from (i)
    55x-45y = -20  
    54x-45y = -27
  (-)   (+)      (+)             
    
   x = 7

Substituting x in (i),

     11x-9y = -4
   11*7-9y = -4
      77-9y = -4
          -9y = -4-77
             y = -81/-9
             y = 9

Therefore, x=7 and y=9
:)