Today John is 3 times older than Mark. If in 13 years, John will be one year younger than twice the age of Mark on that day, how old is Mark today?	Choose the correct choice from the following answers:
A) 12
B) 33
C) 36
D) 38
E) 39
today +13yrs   J =3M 3M+13   M M+13   Given after 13yrs john will be 1 year younger than twice mark's age   i.e 3M+13 = 2(M+13)-1   M=12   12nswer is 12.
<result>A</result>
Today John is 3 times older than Mark. If in 13 years, John will be one year younger than twice the age of Mark on that day, how old is Mark today?