The following data represents the income of a country for a year: 
Calculate the National Income (NI) of the country.
The following data shows the number of students in different streams in a school: 
Which type of graph is best suited to represent this data?
If vector \( \mathbf{a} = 3 \hat{i} + 2 \hat{j} - \hat{k} \) \text{ and } \( \mathbf{b} = \hat{i} - \hat{j} + \hat{k} \), then which of the following is correct?