Question

Five years ago, Nuri was thrice as old as Sonu. Ten years later, Nuri will be twice as old as Sonu. How old is Nuri?

Answer 1

Let the present age of Nuri =x year

And present age of Sonu =y year

Five years ago

➪Age of Nuri =x–5years

➪Age of Sony =y–5years

Nuri was thrice as old as Sonu

➪X−5=3(y–5)

➪X–5=35–15

➪X–3y=−15+5

➪X–3y=−10 ………..(1)

Ten years later,

➪Age of Nuri =x+10

➪Age of Sonu =y+10

Nuri will be twice as old as Sonu.

➪X+10=2(y+10)

➪X+10=2y+20

➪X–2y=10 ………..(2)

➪X–3y=−10 ………..(1)

Subtracting equation (1) from equation (2) we get

➪Y=20

Plug this value in equation first we get

➪X−3∗20=−10

➪X=60–10

➪X=50

Hence age of Nuri =50 years and age of Sonu =20 years

Answer 2

Explanation:

Complete step-by-step answer:

Let us suppose, present age of Nuri be ‘x’ years and present age of Sonu be ‘y’ years.

Now, it is given that five years ago, Nuri was thrice old as Sonu. Hence,

Five years ago,

Nuri’s age = x-5 years

Sonu’s age = y-5 years

And relation between ages can be given as

Nuri’s age = 3××sonu’s age or

x-5 = 3(y-5)

x-5 = 3y-15

x-3y+10 = 0 ………..(i)

Another relation is given in the problem that ten years later, Nuri is twice as old as Sonu.

So, ten years ago,

Nuri’s Age = x+10

Sonu’s Age = y+10

And relation between ages can be written as

x+10 = 2(y+10)

x+10 = 2y+20

x-2y-10 = 0 …………..(ii)

Now we can solve the equation (i) and (ii) to get values of x and ‘y’ or present ages of Nuri and Sonu.

Value of ‘x’ from equation (i) be

x = 3y-10 ……….(iii)

Putting value of ‘x’ from equation (iii) in equation (ii) we get,

3y-10-2y-10 = 0

y = 20

Now, from equation (iii) value of ’x’ can be given as,

x= 3(20)-10

x = 50