First obtain the interest rate on N150.00$R=\frac{I\times 100}{P\times T}=\frac{4.50\times 100%}{150\times \tfrac{5}{2}}=\frac{4.50\times 100%\times 2}{150\times 5}=\frac{6}{5}percent$The interest on N250.00 at $\frac{6}{5}percent$ for ½ year (6month) will be$I=\frac{P\times R\times T}{100}=\frac{250\times 0.5\times \tfrac{6}{5}percent}{100}=\frac{250}{100}\times \frac{1}{2}\times \frac{6}{5}=N\frac{6}{4}=N1.50$