Exercise 3 : Mixing A sample of sand and salt (number of the sand particles = 280 and the salt = 224) mixed for 20 minutes. Then 10 random samples were taken as shown in the below table. Each random sample contains 50 particles. Calculate the mixing index when the time reached 100.87 minutes. Sample No. Number fraction for sand 2 3 4 5 6 7 8 9 10 0.74 0.70 0.64 0.23 0.24 0.46 0.58 0.49 0.67 0.53