Respuesta :

3 multiplied by 4 is 12 
3 multiplied by 7 is 21 

that is how the photos are split 4:7
 4 : 7.......added = 11

4/11 * 33 = 132/11 = 12
7/11 * 33 = 231/11 = 21

so one group has 12 and the other group has 21