Let the common multiple be x.
Therefore, present age of rahul is 5x and present age of haroon is 7x.
After 4 years'
age of rahul will become=(5x+4);
age of haroon will become=(7x+4);
According to the question;
therefore present age of rahul is=5x=5*4=20years.
and present age of haroon is =7x=7*4=28 years.
hope i helped u:)