An oak tree is 6 times as old as a pine tree and an elm tree is 6 years younger than the oak tree In 3 years the age of the elm will be 3 times the age of the pine How old is the oak tree now?

An oak tree is 6 times as old as a pine tree and an elm tree is 6 years younger than the oak tree. In 3 years, the age of the elm will be 3 times the age of the pine. How old is the oak tree now?