SOLUTION: Nica's brother is now 3 times as old as she. In five years, his age will be twice hers. Find Nica's age now. Please provide an equation

Let x be the Nica's age.

Then the brother's age is 3x years.



In 5 years, the brother's age will be (3x+5) years,

while the Nica's age will be  x+5 years.



Therefore, the equation is

    3x + 5 = 2*(x+5).



If you want to solve it, simplify

    3x + 5 = 2x + 15

    3x - 2x = 15 - 5

       x    =   5


Thus Nica is 5 years old now.  The brother is 3*5 = 15 years old.