Question

if Denis is 1/3rd the age of his father Keith now, and was 1/4th age of his father 5 year ago, then how old will his father Keith be 5 year from how? ​

Answer 1

Answer:

Denis age = 20 years

Keith age = 50 years

Step-by-step explanation:

let Keith age be X and Denis age be y

5 years ago

Keith age = x-5

Denis age = 1/4(y-5)

x-5 = 1/4(y-5)

4(x-5) = y-5

4x-20 = y-5

4x-y = 15-----(1)

At present

Keith age = X Denis age = 1/3y

x-1/3y= 0----(2)

By elimination method

4x-y= 15

x-1/3y=0

(2)×4 gives 4x-y = 15

4x-4/3y = 0

(-) (+). (-)

---------------------

1/3y = 15

y = 45

Denis age = 45/3 = 15 years

Keith age = 45 years

5 years later

Denis age = 15+5 = 20 years

Keith age = 45+5 = 50 years