Divide 33 photos into two groups so the ratio is 4:7.

How do you properly write the answer?

4 7

4 7

4 7

4+4+4=12

7+7+7=21

12+21=33

Is that the answer? Or should it be 12/21? Or 12:21?

To do this task the best way is always add both "sides" of ratio and divide whole group by this sum.

sum=4+7=11

33:11=3

Now we know how much is 1 and we can multiply by 4 and by 7 to find the answer.

3*4=12 - first group

3*7=21 - second group

Your result is ok.