Respuesta :

you first set up a proportion 

16/100 = x/90

then cross multiply 16*90
and 100*x 
1440 = 100x
divide each side by 100 
1440/100 = 100x/100 
100 cancels out on the right side 
the answer is 
14.4=x
erae
10% of 90 is 9
5% of 90 is 4.5
1% of 90 is 0.9

So.. 9+4.5+0.9= 14.4