Understanding Normal Distribution

To determine how funny the jokes were, the researchers asked a group of 86 undergraduates to rate the jokes on a scale from 1 (very unfunny) to 21 (very funny). Participants rated a "lawyer joke" as one of the funniest jokes, with a rating of 14.48 4.38 (MSD).

Assuming that these data are normally distributed,

1. How many of the 86 undergraduates gave the joke a rating of at least 10? ***I do not understand how to find the population or or how to solve for a rating of at least 10. I have looked through the Q/A's and unlocked several answers to this question, however most are handwritten and not legible or they only have the steps. I am trying to actually understand how to solve this. Please be very very specific.