Hari is twice as old as Johnny, who is three years older than Rahul. If Hari's age is five times Rahul's age, how old is Johnny?

Suppose the age of Johnny is P years and that of Rahul is Q years.
According to question ,
Age of Hari = 2 × Age of Johnny = 2P
And age of Hari = 5 × Age of Rahul = 5Q
⇒ 2P = 5Q
⇒ 2P – 5Q = 0 ........(i)
Again age of Johnny = Age of Rahul + 3 years
⇒ P = 3 + Q
⇒ P – Q = 3........ (ii)
On solving equations (i) and (ii), we get
Q = 2
∴ Age of Johnny = 3 + Q = 3 + 2 = 5 years
Hence , the age of Johnny is 5 years .