Question

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...?​

Answer 1

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.

Answer 2

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....