How would I produce a mathematical equation using x & y to work out & show how much a joiner has earned?

With pay being linear, express pay as an equation where x= door sets fitted & y= weekly pay.
He earned £280 in week 1 and £360 in week 2 for fixing 10 and 20 door sets respectively.
How would I work out how much he earned if he fits 37 door sets?

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).