A latest generation mobile phone charger uses $1$ W of electric power on standby. Each of the many household appliances which come with the usual black$-$ plastic stand$-$alone power supplies uses ~$3$ W on idle. Assume that you live by yourself in a one$-$person household which features $1$ phone charger and $4$ appliances, and that these are all typically used $20\%$ of the time. How many kWh are going to waste every year if these are left plugged in while they are not being used?

Answer: $91$

Your car consumes the Australian average of $11\mathrm{.}5$ L of petrol per $100$ km and your driving matches the Australian $(2018)$ average of $36\mathrm{.}4$ km per day. Petrol combustion produces $2\mathrm{.}3$ kg CO$2/$L$.$ How many tonnes of atmospheric CO$2$ emissions does your driving generate per year?

Answer: $3\mathrm{.}51$