4) The present age of a father is equal to the square of the present age of his son one year ago, the age of the father was 8times the age of his son find their present age
Answers
Step-by-step explanation:
Let present age of son = x years.
According to question
Now, present age of father = x² years
One year ago :-
Age of father = 8 × Age of son
Present age - 1 year = 8x
x² - 1 = 8(x - 1)
x² - 1 = 8x - 8
x² - 8x + 8 - 1 = 0
x² - 8x + 7 = 0
x² - 7x - x+ 7 = 0
x(x - 7) - (x - 7) = 0
(x - 7)(x - 1) = 0
x = 7, 1
x = 1
neglected
So;
Present age of son = 7 years.
Present age of father = 49 years
Answer:
Present age of son is 7 years.
Present age of father is 49 years.
Step-by-step explanation:
Let,
Present age of son be a years.
So, present age of father should be a^2 years, since age of father is square of the age of son.
One year ago : Age of father was 8 times the age of his son.
= > Age of father that time = 8 x age of son that time
= > Present age - 1 year = 8 x ( present age - 1 year )
= > a^2 years - 1 year = 8( a years - 1 year )
= > a^2 - 1 = 8( a - 1 )
= > a^2 - 1 = 8a - 8
= > a^2 - 8a + 8 - 1 = 0
= > a^2 - 8a + 7 = 0
= > a^2 - ( 7 + 1 )a + 7 = 0
= > a^2 - 7a - a + 7 = 0
= > a( a - 7 ) - ( a - 7 ) = 0
= > ( a - 7 )( a - 1 ) = 0
= > a = 7 or a = 1
Age can't be 1 years, it won't satisfy the situation.
Thus,
Present age of son is 7 years.
Present age of father is 49[ 7^2 ] years
hope it helps u....