Explanation for Question 38 From the Math (Calc) Section on the 2019 March Sat
Question 38 says the number, 2 why is 20% greater in the number X number Z is 20% 3 less than Y the number C is how many times X. 4 So let's start by setting up two separate equations. 5 First we have, Y is equal to six, 6 over five X. 7 And I got that because since X is persons, 8 Y is 20% greater than X. That means that 1.2 X is equal 9 to Y. And then I just took that decimal 1.2 and I transformed that 10 into a fraction. My second equation is that 0.8 Y 11 is equal to Z. And I know that that's true because 12 Z is 20% less than Y. 13 Um, but then I want to transform this into a fraction and isolate Y 14 so I'm just going to change this to eight. Over 10 Y is equal 15 to C. And then when I divide both sides by eight, 16 over 10, I get Y is equal to five over four Z. 17 So now I can set five or four Z equal to six, 18 over five X. I'm going to do that right here. 19 And then I'm going to divide both sides by five, over four to isolate 20 C and I get Z is equal to 21 24, over 25 X, 22 which means Z is 24, over 25 times the value of X. 23 So our answer is 24, 24 over 25.
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