A company manufactures a single product which has the following cost structure based on a production budget of $10\mathrm{.}000$ units.

Materials $-4kg$ at Rs$\mathrm{.}3/$kg Rs$.12$

Direct labour $-5$ hours at Rs$.7$ hour Rs$.35$

Variable production overheads are recovered at the rate of Rs$.8$ per direct labour hour.

Other costs incurred by the company are:

Factory fixed overheads $120,000$

Selling and distribution overheads $160,000$

Fixed administration overheads $80,000$

The selling and distribution overheads include a variable element due to a distribution cost of Rs$.2$ per unit.

The fixed selling price of the unit is Rs$.129.$

Required:

$($a$)$ Calculate how many units have to be sold for the company to breakeven.

$($b$)$ Calculate the sales revenue which would give a net profit of Rs$.40,000.$