Explanation for Question 37 From the Math (Calc) Section on the 2020 October Sat
So question 37 tells us that a car starts out at a $12,000 price. 2 Then we have a little discount and we end up paying a price of 3 $9,600. 4 And so we know that when we have a discount and we're paying a 5 percentage, we can say that we're paying some decimal of it. 6 We can know that we're doing 12,000 times. 7 Some percentage will give us that 9,600. 8 And so we can find X and we'll call X the percent, 9 um, percent of retail that 10 we paid. And we can just find this by dividing both 11 sides here by 12,000. 12 If we do that, we get that. 13 What we paid was 80% of the price, 14 right? So if the car was $12,000 and we ended up paying 9,600, 15 we paid 80% of the retail price. 16 And so you might be tempted to say that 80 is the answer to 17 this question, but if you look forward, 18 it says that the price was decreased by P so the price wasn't decreased 19 by 80%, we paid 80%. 20 And if we started at a hundred percent and we paid 80%, 21 then that means that the price was actually decreased by 20%. 22 And so the value of P is going to be 20.