The sum of the ages of a man and his son is 45. Five years ago ,the product of their age is equal to the 4 times of his father's age at that time .The ages of father and son are...?
Answers
Answer:
Step-by-step explanation:
Let sons age = x years. Then fathers age = (45 - x)years.
(x—5)(45—x—5) = 4(45- x - 5) hence (x—5) = 4 so x = 9
Their ages are 36 years and 9 years.
Let the age of man (father) be x
age of son be y
according to given condition,
x+y=45, that is, x=45-y
five years ago,
age of man=x-5. age of son=y-5
therefore,
(x-5)(y-5)=4(x-5)
xy-5x-5y+25=4x-20
xy-9x-5y+40=0
that is, (45-y)y-9(45-y)-5y+40=0
45y-y²-405+9y-5y+40=0
-y²+49y-365=0
on solving this, as show in the attached image, we get,
y=9.15 OR y=39.85
but man cannot be younger than his son
therefore, substituting y=39.85 in equation 1, we get,
x+39.85=45
x=5.15
therefore, the age of man is 39.85 (or approx.40) and the age of his son is 5.15 (or approx.5)
Hope it helps u...
Thanks....
