How to find variable cost?

what is the units sold ?

Variable cost at present level of activity :54000

now it is easy to find 

Thanks gillbates.

Could also please tell me the proceedure you used to find that?

BTW, how to findout the Variable Cost from this details: Fixed Costs = Rs. 4000, BEP = Rs. 10000.

Variable Cost = 6000

Hint :  At BEP, Fixed cost = Contribution 

so cont. =4000

then Calculate PVR, for finding Sales 

which is 40%

Sales=10000