Question : Directions: 12-year-old Sami is three times as old as his brother Vinay. How old will Sami be when he is twice as old as Vinay?
Option 1: 18 years
Option 2: 14 years
Option 3: 20 years
Option 4: 16 years
Correct Answer: 16 years
Solution :
Given:
Sami's present age is 12 years.
Also, Sami's age = 3 × Vinay's age
⇒ Vinay's age = Sami's age ÷ 3
⇒ VInay's age = 12 ÷ 3
⇒ Vinay's age = 4 years
Let, after y years, Sami's age = (12 + y) years, Vinay's age = (4 + y) years
Also, after y years, Sami's age = 2 × Vinay's age
⇒ (12 + y) = 2 × (4 + y)
⇒ 12 + y = 8 + 2y
⇒ 12 – 8 = 2y – y
⇒ y = 4 years
So, after 4 years, Sami's age = 16 years and Vinay's age = 8 years.
So, Sami will be 16 years old when he is twice as old as Vinay. Hence, the fourth option is correct.