I need help!!!!!!!!!!! PLEASE EXPLAIN! I'M SO CONFUSED! PLEASE!

Answer:
2
Step-by-step explanation:
There are four 11-year olds and x amount of 14-years old.
We are given the average of this group of 11 and 14 year olds is 12.
This gives us the following equation to solve for x:
[tex]\frac{4(11)+x(14)}{4+x}=12[/tex]
Doing some simplifying on the left and writing 12 as 12/1 on the right because I'm going to cross-multiply in the step to follow:
[tex]\frac{44+14x}{4+x}=\frac{12}{1}[/tex]
Cross multiplying:
[tex]1(44+14x)=(4+x)(12)[/tex]
Distribute:
[tex]44+14x=48+12x[/tex]
Subtract 12x on both sides:
[tex]44+2x=48[/tex]
Subtract 44 on both sides:
[tex]2x=4[/tex]
Divide both sides by 2:
[tex]x=2[/tex]
There are two 14-year olds.
Let's confirm.
You have four 11 year olds and two 14 years old.
So you have:
11,11,11,11,14,14
We want to find the average of this set of numbers.
You add the numbers and divide by the number of numbers.
[tex]\frac{11+11+11+11+14+14}{6}=\frac{72}{6}=12[/tex]
This is the average the problem wanted us to obtain so the work we did above is correct.