Dealing with meeting targets in your place of work

I've put money in two Nigerian banks because of banker friends who told me they have a target to meet every month/year. Others have come asking me to help them out, but mehn, how many bank accounts is one supposed to have? I don't know how it works because I've never worked for any company before but it must put a lot of pressure on a worker who needs to meet a particular (money) target every month. Below is something that was sent to a LIB reader by her company...

 1. In-view of the knowledge you have been impacted with on the job, which we believe you can now use to fully benefit (the company) in terms of making profit, salaries will be target based. Which indicates that your monthly salary of N100,000 will be paid fully if you meet a target of N500,000 monthly in terms of getting businesses for (the company)
2. In case you are not able to achieve the set target, a basic salary of N25,000 will be paid and 10% commission on every amount you make for (the company). This takes effect from Tuesday 2nd June, 2015.

So, she said she will now be paid N25k because she can't meet that N500k monthly target. But are companies who demand this, unreasonable or they are within their rights to, because you have to make profit to pay salary, right? What do you guys think?