Admin Control Panel

New Post | Settings | Change Layout | Edit HTML | Moderate Comments | Sign Out O level A level A A1 A2 home private tuition physics chemistry mathematics maths biology trigonometry physics H2 H1 Science Score tutor tuition tuition tutoring tuition biology economics assessment exam exams exampapers exam papers NIE JC Secondary School Singapore Education tutor teach teacher school student agency

O lvl E Maths: Probability

Each member of a class of 30 boys supports one and only one of the three football teams; 13 boys support city, 10 support Rovers, and 7 support United.

(i) If a boy is to be chosen at random, what is the probability that he will support City?
(ii) If 2 boys are to be chosen at random, what is the probability that they will both support City?

Find the probability that
(iii) two boys chosen at random will support the same team.
(iv) two boys chosen will support different teams.

*************************

Answer:

(i) 13/30 (13 boys out of 30 boys)

(ii) P(both boys support City)
= P(1st boy support City) * P(2nd boy support City)
= 13/30 * 12/29
= 26/145

(iii) P(both boys support the same team)
= P(both boys support City) + P(both boys support Rovers) + P(both boys support United)
= 26/145 + 10/30 * 9/29 + 7/30 * 6/29
= 26/145 + 3/29 + 7/145
= 48/145

(iv) P(two boys chosen will support different teams)
= 1 - P(both boys support the same team)
= 1 - 48/145
= 97/145



Related Articles by Categories



Singapore's first free online short to
medium questions and solutions database



Related Posts with Thumbnails