What is the energy differences in Kj/mol for the emission transitions for an electron moving from n=6 to n=3? (Bohr constant is 1312kJ/mol)

Acm ruler with main graduations from 1 to 10 from left to right there are 10 secondary graduations between each of the main graduations there is a line that begins. at the left end of the ruler 10 secondary graduations to the left of the “1 main graduation the right end of the line ends on the eighth secondary graduation to the right of 3 how long is the line