John, who is sixteen years old, is four times as old as his brother. how old will john be when he is twice as old as his brother?

answer; which categories of people are most at risk of becoming a criminals;

the secretary of defense is the principal defense policy advisor to the president. under the direction of the president, the secretary exercises authority, direction, and control over the department of defense.

as you did not provide any choices for me to choose from to give you a direct answer, this is the only information i can provide.