Study

 During their visit to R and As home their grandfather decided to help them study. 

One morning gf asked r what time do we start 10 or 11?

R: after lunch

Next day gf: get your books 

R: you want to spend time with me? Gets his foosball kit

Gf: how did your exam go?

R: I will get above 10

Gf: why? Should get at least 15

R: 15 is above 10 only!