Explanation for Question 3 From the Math (Calc) Section on the 2019 March Sat
Question three says if one, half X minus one, 2 six X equals one, what is the value of X? 3 So to solve this problem, we need to add these two fractions together. 4 So I'm going to start by rewriting this problem out one half X 5 minus one, six X equals one. 6 Now of course, before we subtract one, six X from one half X, 7 we're going to need to change these fractions so that we can actually do 8 that subtraction. They need to have the same denominator. 9 So I'm going to start by multiplying this left, 10 this fraction, the left one half X by three, 11 over three. That way they'll both have the same denominator. 12 And this becomes three over six X minus one, 13 over six X is equal to one. 14 And that just equals two over six X, 15 which is one simplified. One third X is equal to one. 16 So now I need to divide both sides by three or by one third. 17 So multiply both sides by three and we get X 18 is equal to three. 19 And so we know that the answer is C.