Welcome back, Future Einsteins. My name is Yao.
And today we are going to solve this interesting SAT problem.
In the next few month I will post some SAT and elementary math tutor videos for you.
Which one do you prefer?
Just leave the comments below.
Okay, back to the question.
let's read it.
If in 2019 there are 1 more boy and 4 more girls in the school's math club than in 2018.
How many students in total were in
the club in 2019?
Wait a minute, the graph isn't finished.
let's finish it.
Girls is 40% so boys has to be 60%.
Here, boys is 52% so girls
claims 48%.
Okay, so let's start.
This question is fairly easy.
So we can make two variables x and y for the 2019 people in the club and the people in 2018.
But we are only going to use one variable today.
Okay now let's start.
X is going to be the number of students that are in the club in 2019.
Okay, so we know boys claim 52%. So it's 0.52X.
That's how many boys were in the 2019 club.
And how many girls? Let's see, 0.48X since it claims 48 percent.
Now let's see 2018.
It says there are 1 more boy. so if we
subtract 1. It's right here. That's how many in 2018.
Now let's see, the girls.
Girls is 0.48X minus 4, since it just got 4 new students.
Okay what do we do next?
We know that girls claim 40% and boys claim 60%.
So we are going to do the ratio.
The ratio is, 40% / 60%, can be simplified into 2/3.
Now let's do the ratio for this.
Is equal to (0.48X - 4) / (0.52X-1).
So in ratios, there is a property (cross-multiply property. You multiply the opposites and they equal each other.)
So let's see. So 2 * 0.52X is 1.04X minus 2.
Equals, use a different color, so 3 times 0.48x is 1.44X - 12.
Okay now let's erase this part.
Okay, so let's minus 1.04X from each side.
So it's -2 equals 0.4X -12
Now let's plus 12 from each side take
that away and this will become 10.
So now we will conclude that x equals 25.
And since we did X is how students in total were in the club in 2019, the answer is 25.
Yeah, we did it.
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Remember for the next few months, I am going to post some SAT and elementary math tutor videos out.
Which one do you prefer?
Just leave the comments below.
Remember, STEM matters!!
See you next time, FUTURE EINSTEINS!!!
