According to the graph, a student who studies 10 hours per week should earn a score of about how much?

How do i do this? i don’t understand

Edith is shopping for a new leather couch. jordan’s furniture has one that costs $3,000. however, this weekend she can get a 15% discount. how much money will edith save if she buys the couch this weekend? a $15b $2,550c $45,000d $450

Can you explain how a table can be used to find a rate of change?