In a class of 40 students each student plays one indoor game such as ludu,card or oware. Ludu is played by 18, oware is played by 20, while card is played by 27, seven students play ludu and oware, twelve students play oware and card and four students play ludu, card and oware.
Determine how many students play.
(i) Ludu and card
(ii)Ludu and card but not oware.