The graph shows the number of calls (n) Pete made on his mobile phone each month last year and his bill (£b) for the month.
1. Write down the equation of the line of best fit.
b= ?n + ?
2. What is the average cost of each extra call Pete makes?
cost= ? pence
3. Estimate how much Pete would pay in a month when he made 40 calls.
Cost= £?
