Gina is a certain age (g). Gina's older sister is twice Gina's age. Gina's brother is half Gina's age. The sum of their ages is 42. How old is Gina?

Gina is 12 years old

Step-by-step explanation:

First,  we will have to write these statements mathematically and then solve.

Let Gina's age be x, let Gina's brother's age be y and let Gina's sister's age be z.

The second statement"Gina's older sister is twice Gina's age" can be mathematically written as: z =2 x ---------------------------(1)

The next statement "Gina's brother is half Gina's age" can be mathematically written as y = ---------------------------------------(2)

Then the next statement "the sum of their ages is 42" can be mathematically written as: x + y + z = 42 ----------------------------(3)

We can now proceed to solve;

Substitute equation (1) and equation(2) into equation (3)

x + y + z = 42

x +   + 2x = 42

Multiply through by 2

2x + x + 4x = 84

7x = 84

Divide both-side of the equation by 7

=

x = 12

Therefore, Gina is 12 years old

so far i think you have the right thing going for you just remember soh cah toh

step-by-step explanation:

sine over hypotenuse

cosine   equals adjacent

tangent over hypotenuse