Two circus clowns (each having a mass of 50 kg) swing on two flying trapezes (negligible mass, length 25 m) shown in the figure. At the peak of the swing, one grabs the other, and the two swing back to one platform. The time for the forward and return motion is
◦ 10 s
◦ 50 s
◦ 15 s
◦ 20 s
◦ 25 s