In a certain code language, 'x' represents '+', '÷' represents 'x', '-' represents '÷' and '+' represents '-'. Find out the answer to the following question.
Present age of Vikas and Raman are in the ratio of 6 : 5 respectively. If the present age of Rohan is 98 years and the present age of Vikas is 3/7 of the the present age of Rohan, then after how many years the ages of Vikas and Raman would be in the ratio of 7 : 6?