Page 42 - Pra U STPM 2022 Penggal 3 - Maths (T)

Mathematics Semester 3 STPM Chapter 2 Probability
16. The probability that an ambulance from Red Crescent reaches a patient in less than half an hour is
0.83. If the Red Crescent service receives 7500 calls in one year, find the number of patients reached
within half an hour.

17. An ordinary deck of cards contains 52 cards divided into four suits:
The red suits are diamonds (◆) and hearts (♥) and
the black suits are clubs (♣) and spades (♠).
Each suit contains 13 cards of the following denominations:
2, 3, 4, 5, 6, 7, 8, 9, 10, J(jack), Q(queen), K(king), and A(ace).
Penerbitan Pelangi Sdn Bhd. All Rights Reserved.
The cards J, Q, K, and A are called face cards.
(a) State the event that the chosen card is a spade.
2 (b) Find the probability that the chosen card is a spade.

18. A typical personal identification number, PIN, is a sequence of any three symbols chosen from the
26 letters in the alphabet and the 10 digits.
(a) Find the number of different possible PINs, if
(i) repetition is allowed,
(ii) repetition is not allowed.
(b) If all PINs are equally likely, find the probability that a randomly chosen PIN
(i) contains no repeated symbols,
(ii) contains a repeated symbol.

19. (a) Find the number of ways the letters in the word COMPUTER can be arranged in a row if,
(i) there is no restrictions,
(ii) the letters ER must remain next to each other in order as a unit.
(b) Find the probability that the letters ER appear together in order if the letters of the word
COMPUTER are randomly arranged in a row.
20. Two letters are selected at random from the word REJECT. Find the probability that the selection
(a) does not contain the letter E,
(b) contains one letter E,
(c) contains both the letters E.
21. It is forecasted that there is a 40% chance of raining on Tuesday and a 60% chance of raining on
Wednesday. It is expected that the chance of raining on both days is 35%. Determine the probability
that it will rain on either Tuesday or Wednesday.
22. 3 students are chosen from a group of 10 students consisting of 7 boys and 3 girls to represent a school
in chess competition. If the selection is merely based on random picking, find the probability that the
representatives are formed by
(a) 2 boys and 1 girl,
(b) at least 2 girls.

23. Data was collected on the gender of customers entered a supermarket on a particular day. It was found
that out of 360 customers, 249 were female. Estimate the probability that a person who visited the
supermarket on that day is female.
24. Consider the events of drawing a diamond (◆) or drawing a heart (♥) out of a deck of cards.
(a) Determine whether the events are mutually exclusive.
(b) Find the probability of drawing either a diamond (◆) or a heart (♥).
25. Consider the events of drawing a 5 or drawing a heart (♥) out of a deck of cards.
(a) Determine whether the events are mutually exclusive.
(b) Find the probability of drawing either a 5 or a heart (♥).

110

02 STPM Math(T) T3.indd 110 28/10/2021 10:21 AM