Respuesta :

jhonyy9
using the rule of 3 simple 

31 mean 100%
x -------- 70%
------------------------

  x = 70*31/100 = 7*31/10 = 217/10 = 21,7 

so this mean that 70% of 31 is 21,7 

increasing 31 by 70% will result 31+21,7 = 52,7 

hope helped