Question

Ramesh chooses a date at random in January for a party. 

January
Mon		6	13	20	27
Tue		7	14	21	28
Wed	1	8	15	22	29
Thurs	2	9	16	23	30
Fri	3	10	17	24	31
Sat	4	11	18	25
Sun	5	12	19	26

Find the probability that he chooses:  

1. a Wednesday 
2. a Friday 
3. a Tuesday or a Saturday.

Answer 1

Number of possible outcomes = number of day in the month = 31 

n(S) = 31 

i. E = event of selection of a Wednesday = {1, 8, 15, 22, 29} 

n(E) = 5 

Probability of selection of a Wednesday = P(S)

= `"n(E)"/"n(S)"`

= `5/31` 

ii. E = event of selection of a Friday = {3, 10, 17, 24, 31} 

n(E) = 5 

Probability of selection of a Friday = P(S)

= `"n(E)"/"n(S)"`

= `5/31` 

iii. E = event of selection of a Tuesday or a Saturday = {4, 7, 11, 14, 18, 21, 25, 28} 

n(E) = 8 

Probability of selection of a Tuesday or a Saturday = P(S)

= `"n(E)"/"n(S)"`

= `8/31`