tax base amount issue

Hi Experts,

I am posting a document with an input tax code V6 and the tax percentage maintained against this tax code is 8%. The requirement is as follows: The expenditure is Rs. 100 and we need to apply 8% on this and the total invoice amount would be Rs.108.

But while punching the invoice in the system we have inputted the amount Rs. 100 by giving the tax code V6 but the system is calculation a tax amount of Rs.7.40 and the expense is booking at Rs.92.60 and the invoice is booking at Rs100.

Pls guide me to resolve the above issue.