Question $3$: The standard cost of chemical mixture is as thus:

$40\%$ material $R$ at Rs$.25$ per kg$.$

$60\%$ material S at Rs$.40$ per kg$.$

A standard loss of $10\%$ of input is expected in production.

The cost records for a period showed the following usage:

$90kgs$ material $R$ at a cost of Rs$.22$ per $kg.$

$110kgs$ material S at a cost of Rs$.45$ per kg$.$

The quantity produced was $186kgs$ of good product.

Calculate the possible material variances.