142. Solving a chemistry problem

Using the stalagmometer, the following data were obtained: the average number of drops of water 54.7, the average number of drops of the test fluid 88.2. At a test temperature of 17.5 ° C, the surface tension of water is 72.38 • 10-3J / m2. The densities of water and the test fluid are respectively equal: 0.999 g / ml and 1.131 g / ml. Calculate the surface tension of the test fluid.