Question

In school ,there are 3 girls for every 2 boys . There are 650 students in total . How many students are girls ?

Answer 1

Girls = 390

Explanation:

Set up a proportion:

In a sample of 3:2, you have 5 kids in all.

So the the ratio of girls to kids in a sample of 5 is 2:5.

So set up a proportion:

(3/5) = (x/650)

5x = 650(3)

5x = 1950

x = 390

Answer 2

• 390

Explanation:

Let number of boys be b and girls be g. Then we have:

• g/b = 3/2
• g + b = 650

From the first equation b is:

• b = 2g/3

Substitute b in the second equation

• g + 2g/3 = 650
• 5g/3 = 650
• g = 650*3/5
• g = 390