How to calculate cement sand and aggregate quantity in concrete

Given below, the process for material calculation :-

Assume mix ratios of concrete as 1: 1.5:3 where, 1 is for cement, 1.5 is for fine aggregates and 3 is for coarse aggregates of highest size of 20 mm.

The necessary water cement ratio for mixing of concrete is chosen as 0.45

Suppose, bulk densities of materials is given as follow :-