Explanation for Question 33 From the Math (Calc) Section on the Official Sat Practice Test 8
So question three or 33 has given us two equations and they're 2 asking us to solve for C. And so if you see two equations, 3 odds are your natural instinct is to think systems of equations, 4 right? But the reason that systems equations isn't going to work in this case 5 is because we actually have three variables. 6 We have X, we have Y and we have seat. 7 Now, if we have three variables, that means we need three equations. 8 But in fact, we only have two or one equation short. 9 So systems of equations is not the strategy for this question. 10 We need to think of something else. And now they tell us that C 11 is a constant, right? So I'm going to write these two equations and I'm 12 going to line them up so that we can see a little bit better. 13 What is happening between these equations? 14 Now, if I look at my X term, I could see that multiplied by 15 three, right? Cause X times three is three X. 16 If I look at my wife's room, I can see that I've also multiplied 17 by three cause two Y times three is six Y. 18 So if I want to find, see, it makes sense that I should just 19 take whatever's in my top equation and multiply by three and 10 times three 20 is 30. And so our best answer is going to be 30.