[Video] Q6: H = 3a + 28.6 a pediatrician uses the model above to estimate the height h of a boy, in inches, in terms of the boy’s age a, in years, between the ages of 2 and 5. based on the model, what is the estimated increase, in inches, of a boy’s height each year?

Explanation for Question 6 From the Math (No Calc) Section on the Official Sat Practice Test 1

So number six gives us this equation here and it tells us that a 2 pediatrician uses the model to estimate the height H of a boy. 3 So we know the H represents our height in inches in terms of the 4 boys age a in years. 5 So we know that the a right here is the age between the ages 6 of two and five, based on the model, what is the estimated increase in 7 inches of a boys' height each year? And so we see that we're talking 8 about the increase each year. 9 And so we basically have two options here, 10 right? We can choose the three or we can choose the 28.6, 11 right? Cause those are our two numbers that come in our equation. 12 And if we want to think about something, being a rate, 13 that's made an increase, right? We're talking about a rate here that we know 14 that the number that's, our slope is going to be our change, 15 right? 16 Because our slope is the rate that happens. 17 Whereas this 28.6 would be our starting point. 18 So that would be the boys' height at the beginning. 19 Right? But since we're talking about a rate, 20 since we're talking about the increase in inches each year, 21 we want to choose something that's actually connected to the years that pass right? 22 The age. In this case, we have the three a, 23 so our best is going to be three. Another way you could do this 24 is plug into ages, right? You could plug into and you could plug in 25 three, which has an age difference of one year. 26 And then you would see that the difference between the two of those is 27 three inches and you could choose answer choice a.