[Video] Q22: The sum of three numbers is 855. one of the numbers, x, is 50% more than the sum of the other two numbers. what is the value of x ?

Explanation for Question 22 From the Math (Calc) Section on the Official Sat Practice Test 3

Not for question number 22. It tells us the sum of three numbers is 2 855. One of the numbers, 3 X is 50% more than the sum of the other two numbers and we're 4 going to solve for X, right? So let's call our numbers X, 5 Y, and Z. And so we know now from that first sentence that X 6 plus Y plus Z is equal to 855. 7 Right? And then it tells us that X is 50% more than 8 the sum of the other two numbers, right? So X is 50% more than 9 Y plus Z. And so to show that it's 50% more, 10 we're going to multiply by 1.5, 11 right? Cause that one is kind of like our starting point. 12 And that 0.5 is the 50% more. 13 Right? So by multiplying by 1.5, we're showing that we have all of Y 14 plus Z the original amount and an extra 50%. 15 So now what we can do here. 16 So we've got the sum of the three numbers. X is 50% more than 17 the sum of the other two numbers. 18 Um, and so what is the value of X? 19 Right? So what we can do here is we can take this 1.5 times 20 Y plus Z and plug it in to our topic equation. 21 And when we plug it into our topic equation, 22 we can see that it would be rewritten is 1.5 times Y plus 23 C plus Y plus Z is equal to 8 55. 24 And so we can go ahead and distribute out this 1.5. 25 So that's 1.5 Y plus 1.5 Z plus Y plus Z 26 is equal to 8 55. And so you'll notice right now that we have one 27 equation, but we have two variables in it. So we'll never adjust, 28 be able to solve for just Y or just Z. 29 But luckily to find the value of X we don't need to solve ...