It definitely depends on the sect of Judaism and the readings and teachings one chooses to look at, but I would argue that the afterlife just isn’t a core piece of modern Judaism for millions of Jews. It also isn’t a religion that tries to convert others, which is another way it differs from the other monotheist Abrahamic religions
You can’t divide only some parts by 3:
Either first simplify:
3n - 6 < 30
3n < 36
n < 12
Or divide everything by 3:
3n - 6 < 30
n - 2 < 10
n < 12