im doing my homework and i need help.

Question

Rick has 

3/

5

 of a liter of orange juice and 

2/

15

 of a liter of apple juice. He says that he has 

5/

20

 of a liter of juice in total. Is Rick's statement reasonable?

Answer 1

3/5 + 2/15 = 9/15 +2/15 = 11/15

5/20 = 1/4

11/15 > 1/4

his claim is unreasonable

his mistake was to add numerators 3+2 and add denominators 5+15 to get 5/20