2. Add \a and 1/3. Use 12 as the common denominator

Step-by-step explanation:

Since I have to assume a is part of the fraction. We will answer assuming /a is replaced with a/12 + 1/3

To write 12/a as a fraction we must multiply with a common denominator. Thus being 3/3.

Now to write 1/3 as a fraction with a common denom we must use a/a.

Then we want to write each expression with a common denominator of a * 3 and multiply by a factor of 1.

Then we want to multiply 1/3 and a/a.

Then we reorder the factors of a *3.

Next, we combine the numerators over the common denom.

FInally, we multiply 12 by 3.

36 girls

step-by-step explanation:

the 48 boys is 4 parts of the ratio

divide 48 by 4 to obtain one part of the ratio

= 12 ← 1 part of the ratio

3 parts = 3 × 12 = 36 ← number of girls