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
$$y = \frac{1}{10}x(20 - x), \quad 0 \leq x \leq 20.$$
- Complete the table below, giving values of \(y\) to 3 decimal places.
| \(x\) | 0 | 4 | 8 | 12 | 16 | 20 |
| \(y\) | 0 | | 2.771 | | | 0 |
[2] - Use the trapezium rule with all the values in the table to estimate the cross-sectional area of the river.
[4]
Given that the cross-sectional area is constant and that the river is flowing uniformly at 2 m s⁻¹,
- estimate, in m³, the volume of water flowing per minute, giving your answer to 3 significant figures.
[2]