Explanation for Question 13 From the Math (No Calc) Section on the 2018 March Sat
Question 13 says the number of microscopic organisms in a Petri dish 2 grows exponentially with time, the function P above models, 3 the number of organisms after growing for tea days in the Petri dish, 4 based on the function, which of the following statements is true. 5 Now, before we look at these statements, 6 uh, let's just look at the equation up here and see what this means. 7 So whatever number is in the parentheses tells you what the rate of increase 8 or decreases. So since this number is three, 9 we know that this, uh, original value is tripling. 10 So that means that we can eliminate answer choices, 11 B and D. And we know that a triples when 12 this value is equal to one. So all we have to do is set 13 T over two equal to one and solve for T that gives us T 14 is equal to two, which means that when T is equal to two, 15 the number of organisms in the Petri dish, 16 triples since T represents the number of days, 17 that means that every two days the number of organisms triples, 18 which means that the correct answer here.