A mother's age is $3$ times older than her older son and $7$ times older than her younger son (She has only two sons). The older son will be $50$ years old when the younger son is same age as his mother's current age. What is the mother's current age?
Let's call them as $M$, $O$ and $Y$.
$$M = 3O \tag{1}$$ $$M=7Y \tag {2}$$
and
$$O - Y = 50 - M\tag{3}$$
This is where I'm stuck. Can you take a look?
With My Warnest Regards!