I'm missing something here? For sure to me an 88 isn't divisible by 15 (the shapes) so I'll go with 90 and @Adey1980
Not being the sharpest tool in the box and leaving school with no decent exam results I'll accept your argument.
I will say, however,that I still think it's 88. For me it would only be 38 if the multiplication was in brackets so you calculated that sum before applying it to the rest of the calculation.
Probably explains why my setting out is crap!