Two years ago a man's age was three times the square of his daughters age. Three years hence his age will be four times his daughter age. What is the present age?
Answers
Answer:
Step-by-step explanation:
2 yrs ago:
daughter=x
thrfr, man = 3x²
present:
daughter=x+2
man = 3x²+2
3yrs hence,
daughter = x+5
man = 3x²+5
but,
3 yrs hence,
man = 4 times the age of daughter.
therefore,
4(x+5)=3x²+5
4x+20=3x²+5
4x+15=3x²
3x²-4x-15 = 0
3x²-9x+5x-15=0
3x(x-3)+5(x-3)=0
(x-3)(3x-5)=0
either,(x-3) = 0 or (3x-5) = 0
thrfr, x=3 or x = 5/3
rejecting 5/3 since age cannot be in decimals.
therefore,
present:
daughter = x+2 = 3+2 = 5yrs
man = 3x²+2 = 27+2 = 29yrs
hope it is helpful
First make expression satisfying the given condition. We'll be likely to get a quadratic equation. Then solve it using quadratic formula.
On solving the equation we'll get the age of the man= 29 years
And that of his daughter = 5 years.
Detailed explanation is given in the photos.
Hope it helps
