tuition was 2800 obtain 3/7 of the loan. how much was loan?

However, if you mean that 3/7ths of the loan was $2800, then the way to solve it is:

         (3/7)(loan) = 2800

multiply both sides times 7/3:

         (7/3)(3/7)(loan) = (7/3)(2800)

                         loan  =  7/3 x 2800

Are you asking that: if tuition was $2800.00 and you received a loan for 3/7ths of the tuition, how much is the loan?

If so, multiply 3/7 times 2800:  (3/7) x $2800 =  the answer.

You can use the calculator at this site to obtain the answer.