Solving Systems Using Substitution: The population of a city is 2,500. If the number of males is 240 more than the number of females, how many males and females are there in the city?

Answer 1

Break the problem down into its parts.

Total population 2,500

There 240 more females than males.

Now let's write down what we know from the information provided.

Let's call number of females x

Females = ×

We know that are 240 more males

Males = x + 240

And a total population of 2,500

Males + Females = Total Population

(×+240) + × = 2,500

2x + 240 = 2,500

2x = 2,260

x = 1,130

We stated x was females

Thus...

Females - 1,130

Males - 1,130 + 240 = 1,370

Answer 2

First, let the number of males be represented by variable M and females by F

The population M+F = 2,500

Since males are more by 240, the equation will be set up like this; M = F + 240

Replace the M in the first equation by (F+240) and solve for F;

So, (F+240) + F = 2500

2F+ 240 = 2500

Subtract 240 from both sides;

2F = 2500 -240

2F = 2,260

Then divide both sides by 2 ;

F = 2,260 / 2

F = 1,130

If F is 1130, replace the variable F in any equation to solve for M;

I'll use ; M+F = 2,500

M + 1,130 = 2,500

M = 2,500 - 1,130

M= 1370

Therefore, there are 1,130 Females and 1,370 Males.