Hey there! I'm happy to help!
30% is the same thing as 0.3, which is 30% of 1.
0.3 is what you multiply numbers if you want to see what 30% of that number is as 0.3 is 30% of 1, the whole number.
3/10 is the same value as 30% because 3 divided by 10 is equal to 0.3, which is 30%.
The dots in the boxes are also the same thing as 3/10. There are 10 boxes, and 3 out of the 10 have dots, which is 3/10 and 30%.
The one that does not belong is 0.333333...... This is equivalent to 1/3, which is greater than 30%, 0.3, and 3/10.
Have a wonderful day and keep on learning! :D