Solving a problem in physics section 42 point 66 optics

66. The glucose solution with a mass concentration C1 = 0,21 g / cm3, which is in a glass tube rotates the plane of polarized monochromatic light transmitted through the solution at an angle φ1 = 24 °. Determine the weight concentration C2 of glucose in the other solution in the tube is the same length if the plane of polarization rotates by an angle φ2 = 18 °.