There are 3 events that numbers picked is greater than 7 from 10 events, those are 8,9,10.
The complement of event A is the event that number picked is lower or equal to 7. The numbers represent the complement of event A are 1,2,3,4,5,6,7. There are 7 events..
The probability of the complement will be
P = [tex] \dfrac{\text{the number of complement of event A}}{\text{total number of events}}[/tex]
P = [tex] \dfrac{7}{10} [/tex]
ANSWER: D) 7/10