Applicable tax rate in this cse

As per slab rate with interest and penalty. The penalties can range from Rs 100 to a maximum of 300% of the tax sought to be evaded, in addition to the tax payable. 

As per newly inserted Section 270A (which has replaced section 271 of the income-tax Act), if an individual is found to have underreported her income, a penalty equal to 50% of income tax payable may be levied. However, in cases of “misreporting of income," penalty equal to 200% of the income tax payable may be levied.

interest rate is 18% p.a.