6. A river, running between parallel banks, is 20 m wide. The depth, \(y\) metres, of the river measured at a point \(x\) metres from one bank is given by the formula
$$y = \frac { 1 } { 10 } x \sqrt { } ( 20 - x ) , \quad 0 \leqslant x \leqslant 20$$
- Complete the table below, giving values of \(y\) to 3 decimal places.
| \(x\) | 0 | 4 | 8 | 12 | 16 | 20 |
| \(y\) | 0 | | 2.771 | | | 0 |
- Use the trapezium rule with all the values in the table to estimate the cross-sectional area of the river.
Given that the cross-sectional area is constant and that the river is flowing uniformly at \(2 \mathrm {~ms} ^ { - 1 }\),
- estimate, in \(\mathrm { m } ^ { 3 }\), the volume of water flowing per minute, giving your answer to 3 significant figures.