The ratio of boys to girls in a class is 2:4. If there are 24 students total in the class, how many of them are boys?

Feb 26, 2018

There are $8$ boys

Explanation:

Firstly, we can simplify the ratio of boys to girls to $1 : 2$.

Then, to find out how many students each ratio represents, we add up $1$ and $2$ to get $3$ ($1 + 2 = 3$).

By dividing $3$ by the number of students, we can find how many students ONE ratio represents: $\frac{24}{3} = 8$.

So ONE ratio is equal to $8$ boys. Since our simplified ratio of boys to girls is $1 : 2$ already, we do not have to do further multiplying - the number of boys is simply $8$.

For the girls, simply multiply $2$ by $8$ to get $16.$

Check: $8$ $\text{boys}$ $+ 18$ $\text{girls}$$= 24$ $\text{students}$.

Feb 26, 2018

$8$

Explanation:

Multiply every number by $4$.

If two boys and four girls gives a class size of six, then keeping the $1 : 2$ ratio, $8 : 16$ gives a class size of $24$.

An easy way to think of it is in fractions

$\frac{2}{4} = \frac{1}{2}$

but $2$ is really $1 + 1$. Now you have three students, so every ratio has to give a class size that's $3 x$. If

$3 x = 24$

then you can just divide by $3$ to give you your answer because the boy's is one-third of the entire class. To find the girls, it's $2 : 3$, or $1.5$.

Just divide $24$ by $1.5$ to find your $x$ value $\left(16\right)$. To double check our answer, does

8+16=24?

and does

8/16 = 1/2" " ?