taxable income

Anthony and Latrisha are married and have two sons, James, age 25 and Jonas, age 13. Both sons are properly claimed as dependents. Anthony and Latrisha's marginal tax rate is 25% in the current year and they file a joint return. Both James and Jonas had part-time jobs as well as some unearned income. Below is a summary of their total income.
James Jonas
Wages: $2,800 $400 
Taxable interest: 1,800 2,000 
Required:
Compute the taxable income and tax liability for James and Jonas.