[Video] Q2: If y = kx, where k is a constant, and y = 24 when x = 6, what is the value of y when x = 5 ?

Explanation for Question 2 From the Math (Calc) Section on the Official Sat Practice Test 1

Now question number two says that if Y is equal to K X and 2 K is a constant and Y is equal to 24, 3 when X is equal to six, what is the value of Y when X 4 is equal to five? So first thing we can look at our question. 5 We see that it wants us to find the value of Y when X 6 is equal to five. So if we plug that in, we get, 7 Y is equal to K times five. What we'll notice is that we're missing 8 K in order to find why we need to know what K is. 9 And that's where this first bit of information comes into play. 10 Going back to our original equation, Y equals K X. 11 It tells us that when Y is 24, 12 X is equal to six. Now I can use this information to solve for 13 K. What I need to do is divide both sides by six. 14 And I get that four is equal to K and it also says that 15 K is a constant. That means that K is never going to change. 16 So if K is four for this equation, 17 then K is also for, in this equation, 18 right? So Y is going to be equal to not K, 19 but four times five and four times five is equal to 20. 20 So Y is going to be equal to 20, which leads us to answer 21 choice C.