[Video] Q1: John runs at different speeds as part of his training program. the graph shows his target heart rate at different times during his workout. on which interval is the target heart rate strictly increasing then strictly decreasing?

Explanation for Question 1 From the Math (Calc) Section on the Official Sat Practice Test 1

So question number one is asking us on what intervals does John's heart rate 2 increase then decrease. Now, if we look at a, 3 between zero and 30, we see that we increase and then we stay the 4 same. There is no decrease here. So that's why a is wrong. 5 Now be on 50 to 65 at 50, 6 we decrease and then we increase the 65. 7 So for C we actually decrease it and then we go to increase. 8 But what we're looking for is increase and then decrease. 9 So C has the opposite order. That's why C is incorrect. 10 Now the 70 to 90, 70, 11 we see staying the same, then a quick jump and then staying constant. 12 Right? So 70 never has a decrease, just like, 13 eh, so that's why D is wrong. 14 And then finally, B, if we look at V we see that we increase 15 and then we decrease, which is exactly what we wanted from the question. 16 So our best answer is going to be B.