Top line shows that a shoe is 5 (if we assume two symbols together are to be added, not multiplied. Personally I have an urge to multiply concatenated symbols ...)
So, top line two shoes+ two shoes + two shoes = 30. One shoe is 5
Next line: boy + boy + two shoes = 20. One boy = 5
Next line: 2 cones + 2 cones + 1 boy = 13; 2 cones = 4; 1 cone = 2
Final line: shoe + boy x cone = 5+5x2 = 20