Estimation Golf with Timer

mathleague.org has a Number Sense competition, where every 10 problems is an estimation problem. To help practice estimation, one could try Estimation Golf. You can also watch a video about estimation at https://www.khanacademy.org/math/arithmetic/multiplication-division/multi_digit_multiplication/v/multiplying-whole-numbers-and-applications-4 A version of Estimation Golf (see http://mrnussbaum.com/estimationvalley/ or http://users.stlcc.edu/Departments/fvmath/Excellence%20in%20Math%20Contest.htm for other versions). You have the option of three types of problems: Linear, Exponential or Rational You have the option of three difficulty levels: Easy, Medium, Hard You are to enter your guess. The program will keep track of your guesses and whether f(x) is in the appropriate range. The result it gives you is whether f(x) (not x) is too high, too low, or in the appropriate range. The first time you run GeoGebra with Java it may take a long time (4-5 minutes) for everything to load.
The object is to guess an x-value that satisfies the inequality in as few attempts (strokes) as possible. BUT, only about 2 minutes per stroke are allowed or you get a penalty stroke.