Need help with these miscellaneous calculus questions.

3. A particle moves along a horizontal line with a positive velocity , where v is a differentiable function of t. The time t is measured in seconds, and the velocity is measured in cm/sec. The velocity of the particle at selected times is given in the table below. t (sec) 0 2 4 6 8 10 12 v(t)(cm/sec) 37 17 5 6 17 38 a. Based on the values in the table, what is the smallest number of times at which the velocity of the particle could equal 20 cm/sec in the open interval 0