Question

In a group of 80 children, there are three times as many boys as girls. How many are there?

Answer 1

In the given question, there are several vital information's provided and they can be used to determine the required answer. Firstly it is already given that there are a total of 80 students in the group. It is also given that the number of boys is 3 times that of the number of girls.Then:
Let us assume that the number of girls in the group = x
Then the number of boys in the group = 3x
Now we can put the above information's to gether to find the number of boys and girls.
x + 3x = 80
4x = 80
x 80/4
x = 20
Then we can say that there are 20 girls in the group.
The number of boys = 3x
                                  = 3 * 20
                                  = 60
Then there are 60 boys in the group.

Answer 2

b ... the number of boys
g ... the number of girls
80 children

three times as many boys as girls ... 3 * g = b

If you would like to know how many boys and girls are in a group of 80 children, you can calculate this using the following step:

b + g = 80
3 * g + g = 80
4 * g = 80    /4
g = 80/4
g = 20 girls

b = 3 * g = 3 * 20 = 60 boys

Result: There are 60 boys and 20 girls.