524. When light passes through a tube with a length of l1 = 20 cm containing a sugar solution with a concentration of C1 = 10%, the plane of polarization of the light is turned through an angle φ1 = 13.3 °. In another sugar solution, poured into a tube l2 = 15 cm long, the plane of polarization turned through an angle φ2 = 5.2 °. Determine the C2 concentration of the second solution.