Question

the differences of the ages of Two Sisters is 5 years after 4 years if the product of their ages become 104 find their present age ​

Answer 1

Answer:

Let the sister and her sister's age be X yrs and X+5 yrs respectively.

Let the sister and her sister's age be X yrs and X+5 yrs respectively. As per the question,

X(X+5)=104

X² +5X−104=0

+5X−104=0 X²+13X−8X+132=0

X(X+13)−8(X+13)=0

(X+13)(X—8)=0

∴X=8orX=−13

∴ the ages of sisters are 8 years & 8+5=13 years respectively, as the age can't be negative.

Answer 2

Soln,

Let, the present age of elder sister be x+5 and younger sister be x, respectively.

From the question,

x(x+5)=104

x²+5x-104=0

x²+(13-8)x-104=0

x²+13x-8x-104=0

x(x+13)-8(x+13)=0

(x+13)(x-8)=0

Either,

x+13=0 or,x-8=0

x=-13. x=8

:Age can't be negative.

So, the age of elder sister = 8+5=13

and the age of younger sister = 8.