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 John today?
I just cant understand how this was solved.
today john is 3 times mark , this means J = 3M...........................1
in 13 years
j = J + 13
M = M+13
John will be one year younger than twice the age of Mark on that day
m = 12
therefore j = 36