Gross amount is 350. Received check 335 after deduction which is 2% and 6% of the gross amount i.e 350. I want to know 2% and 6% deduction amount with solution.

Why don't you phone or contact the people who wrote you the check and ask them what the deduction was for.

$15 is 4.5% of $350. (actually $15.01)
Please explain better what you mean.

Educated guess would be some type of commission or fee, or perhaps state or local income tax withholding.