To determine how many more apples the third grade picked than the fifth grade, let's first calculate the number of apples picked by each grade based on the given information:
- Grade 2: 2 whole apple pictures = 2 * 10 = 20 apples
- Grade 3: 4 whole apple pictures + 1 half-apple picture = (4 * 10) + 5 = 40 + 5 = 45 apples
- Grade 4: 5 whole apple pictures + 1 half-apple picture = (5 * 10) + 5 = 50 + 5 = 55 apples
- Grade 5: 3 whole apple pictures = 3 * 10 = 30 apples
Now, we can find the difference between the number of apples picked by the third grade and the fifth grade:
Number of apples picked by third grade = 45 apples
Number of apples picked by fifth grade = 30 apples
Difference = 45 - 30 = 15 apples
Thus, the answer is 15 apples.