Quartz vibrates at about 2.5 million pulses each second. Caesium vibrates at about 9 192 631 770 vibrations per second.

(i) Write both these numbers in standard form

(ii) Calculate how many more times per second caesium vibrates than quartz

14. Jane earns £16500 a year before tax. She doesn’t pay tax on the first £2800 that she earns. How much income tax does she pay a year when the rate of tax is 35%?

15. The population of Australia is 18 million, of which 3.5 million people live in Sydney and 1 million people live in Perth. What fraction of the population live in Sydney?