a geometry class has a total of 40 students. The number of males is 12 more than females. How many males and how many females are in the class?

Question

Need a little help form my friends.

Answer 1

Sometimes when the same situation is described two different ways, it is a system of equations problem.  They gave you a clue about the number of males.  We don't know but they did say that there are 12 more females than males.  In math, that means m=12+f.  We also know that the total of males and females is 40, which can be written as m+f=40.  Those were the two descriptions and the 2 math sentences to solve this problem

 

 

f = number of females

m=12+f

f+m = 40

 

Now substitute

f + 12+f = 40

 

add like terms

2f +12 =40

 

Now solve the equation for f.  Remember:  you can check your answer because the total males and females will add up to 40

Answer 2

Total students = 40

 

number of females = x

 

number of males = x+12

 

so when you add number of males and females in this class they must add up to 40

 

so you add x with (x+12)   and set that equal to 40

 

 

(x)+(x+12) = 40

 

there are two x so they add up to 2x

 

2x+12 =40

 

you want to subtract that 12 from lefthand side and right hand side so,

 

2x =40-12

 

2x = 28

 

divide both side by 2 so you get x by itself

 

x = 14

 

 since x is females there are 14 females in the class and there are 14+12 = 26 males in the class

 

Answer 3

What is the number of females?  Good!  You (already) said "I don't know."

That is the correct answer.  Give yourself a point.

When we don't know, what do we put in algebra?

An x.

 

x = number of females;

x + 12 = number of males:

 

x +  (x + 12)  =  40

 

Solve for x for the number of females.  Then you can find the number of males.