This post is on Virgin Mobile SA's Facebook page:
"Did you know our new Prepaid product gives you 30% off normal
airtime charges? That's right! Get R10 Free airtime for every R30 you use!"
I know it's kinda pedantic but that maths is wrong on two counts. Firstly one third is 33% not 30%, and secondly it's 25% off, not 30% (or 33%).
What they're offering is a 33% airtime bonus (which is pretty good) but that isn't the same as getting 33% off.
</maths and english pedant>