five years a woman age was a square of her son age 10 years is hence her age be will twice that of his son find
1, find age of her son 5 years ago and
2, find the present age of women
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Answered by
6
Let the present age of woman be " x yrs " and that of the his son be " y yrs ".
By the first condition
( x - 5 ) = ( y - 5 )²
=> x - 5 = y² - 10y + 25
=> x - y² + 10y = 30. ... ( 1 )
By the second condition
( x + 10 ) = 2 ( y + 10 )
=> x + 10 = 2y + 20
=> x - 2y = 10. ... ( 2 )
Subtracting equation ( 2 ) from equation ( 1 ) we get
- y² + 12y = 20
=> y² - 12y + 20 = 0
=> y² - 10y - 2y + 20 = 0
=> y ( y - 10 ) - 2 (y - 10 ) = 0
=> ( y - 10 )(y - 2 ) = 0
=> y - 10 = 0. or. y - 2 = 0
=> y = 10. or. y = 2 .
y = 2 is not possible because 5ago years ago his age will be negative.
So y = 10
Putting y = 10 in equation ( 2 )
x - 2( 10 ) = 10
=> x - 20 = 10
=> x = 30 .
Answered by
0
let women present age of women =x
10 years ago her age = x+10
son age will be =1/2× x+10
=×/2+5
present age of son = x/2 +5-10
=×/2 -5
5 years ago =
then x-5 =( x/2-5- 5)^2
x-5= (x/2-10)^2
factorise it and the value if x will be the mothers present age ..
and u can get all ages bu putting value of x in them..
nehajaglan:
this is the second method...
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