provide answer with every step asap

The Standard Cost of Chemical mixture 'PQ' is as follows: 40% of material P @ Rs.400 per kg. 60\% of material Q @ Rs.600 per kg. A standard loss of 10% is normally anticipated in production. The following particulars are available for the month of March, 2004. 180kgs of material P have been used @ Rs.680 per kg 220kgs of material Q have been used @ Rs.360 per kg. The actual of production of 'PQ' was 369kgs. Calculate the following variances: a) Material Price Variance b) Material Usage Variance c) Material Mix Variance d) Material Yield Variance