Question

Stable High School has a total of 112 boys and girls who play sports. If the number of boys, b is 16 more than twice the number of girls, g, how many boys play sports at this high school?

Answer 1

80 boys play sport.

Explanation:

`b = "number of boys" and g = "number of girls"`

There are 112 students altogether.

`b + g = 112`

This can also be written as
`b = 112 - g" or as " g = 112 -b"`

It is very useful to have variables as the subject of the equation when working with simultaneous equations. This allows for easy substituting or equating.

A common mistake is to add to the boys and to multiply the boys by 2. There are more boys! - do not make them even more.

`b = 2g +16`

There are now 2 equations.

`b = 2g +16" "` and `" "b = 112 - g`

`b= b` therefore it follows:

`2g +16 = 112-g`

`3g = 112-16`
`3g = 96`

`g = 32`

`b= 80`