Let the total amount of money be x.
Then, A gets \(\frac{3x}{15}\) of the total amount.
B gets \(\frac{5x}{15}\) of the total amount.
C gets \(\frac{7x}{15}\) of the total amount.
Given, B gets Rs. 300 more than A.
So, \(\frac{5x}{15} - \frac{3x}{15} = 300\)
=> \(\frac{2x}{15} = 300\)
=> \(x = 300 \times \left(\frac{15}{2}\right) = 2250\)