Respuesta :

312.5/x=100/12.8
(312.5/x)*x=(100/12.8)*x     
312.5=7.8125*x       
312.5/7.8125=x 
40=x 
x=40
40
all you have to do is multiply 312.5 • 0.128
you have to make 12.8% a decimal so you move your decimal two places to the left = 0.128