What is £300 divided into a ratio of 3: 7

Can someone me with this problem i don't understand i need

Nick has box brads. he uses 4 brads for the first project. nick let’s b represent the original number of brads and finds that for the second project, the number of brads he uses is 8 more than half the difference of b and 4. write an expression to represent the number of brads he uses for the second project.

Write the pair of fractions as a pair of fractions with a common denominator