Final answer:
The experimental probability of spinning a sum of 7 is 1/4 or 0.25.
Step-by-step explanation:
To find the experimental probability of spinning a sum of 7, we need to determine the number of times a sum of 7 was landed on out of the total 20 spins.
The student mentioned that a sum of 7 was landed on 5 times. Therefore, the experimental probability of spinning a sum of 7 is 5/20, which can be simplified to 1/4 or 0.25.
In conclusion, the experimental probability of spinning a sum of 7 is 1/4 or 0.25.