Mei is making fruit punch. She makes the fruit punch by mixing fruit juice and lemonade in the ratio 1 : 3.
The fruit juice costs £1.80 per litre.
The lemonade costs 75p per litre.
Work out the total cost of making 16 litres of fruit punch.

The input to the function is x and the output is y. write the function such that x can be a vector (use element-by-element operations). a) use the function to calculate y(-1.5) and y(5). b) use the function to make a plot of the function y(x) for -2 ≤ x ≤ 6.