Question

Paul is 12years old .He is thrice old as his brother.How old paul be when he is twice as old ashis brother?

Answer 1

Given:

• Paul' age = 12 years

To Find:

• Paul's age when he is twice old as his brother.

Solution:

• Let "x" be paul's age, x = 12
• Let y be his brother's age, x=3y
• substitute value of x in the above equation, y = 12/3 = 4 years.
• His brother was 4 years when paul is 12 years.
• So paul is 12-4 = 8 years older than his brother.
• We can form an equation stating, y = x - 8 → (1)
• Now, paul is twice old as his brother, x = 2y → (2)
• substitute (2) in (1) we get, y = (2y) - 8 ⇒ -8 = -y ⇒ y=8
• substitute y = 8 in (1)
• 8 = x - 8 ⇒ x = 16

∴ Paul will be 16 years, whenhis brother is 8 years.