Please help me with the following question​

How do i get the answer for 2/3 * 10/3

The graph shows the distance y, in inches, a pendulum moves to the right (positive displacement) and to the left (negative displacement), for a given number of seconds x. how many seconds are required for the pendulum to move from its resting position and return? enter your answer in the box.

Can someone me out here and the tell me the greatest common factor