Total number blood donors = 85
(i) Number of donors whose blood is useful for Cheeku = 3
\(\therefore \) Number of favourable events = 85 - 3 = 82
Now, required probability\(=\frac{82}{85}\)
(ii) Responsible, rationality, love
(iii) Blood donation helps the needy. In fact it is a great act of charity and co-operation.

(i) Number of test in which the student scored more than 70%marks=3
P(more than 70%marks)\(=\frac{3}{6}=\frac{1}{2}\)
(ii) Number of test in which the students scored less than 70% marks =3
P(more than 70% marks)\(=\frac{3}{6}=\frac{1}{2}\)
(iii) Number of tests in which the students scored at lear 60% marks=5
P(at least 60% marks) = \(\frac{5}{6}\)

(a) Probability that a student selected is opts French language = \(\frac{12}{50}=\frac{6}{25}\)
(b) Probability that a student selected does not opt for Japanese = 1-selected student opts Japnese
(c) Probability that selected either opts for Sanskrit or for German = Prob. of student opts Sanskrti+ Prob. of students opts German
\(\therefore \)No of student who opted German 
= 5 - (14 + 08 + 12 + 6)
= 50-40
= 10
\(\therefore \)Prob. that selected student either opt for Sanskrit or for German
\(=\frac{14}{50}+\frac{10}{50}\)
\(=\frac{24}{50}=\frac{12}{25}\)

Total student = 7 + 7 + 11 + 3 + 5 + 9 + 8 = 50
(i) P(height of student is more that 135 cm)\(=\frac{25}{50}=\frac{1}{2}\)
(ii)P(height of student is at least 145 cm)\(=\frac{17}{50}\)
(iii) p(height of student is less than 130 cm)\(=\frac{14}{50}=\frac{7}{25}\)
(iv) P(height of student is 125 or more but less than 140)\(=\frac{21}{50}\)

Total number of cards in the deck when king, queen, and jack of clubs are removed
= 52 - 3 = 49
(a) Number of cards which are 'a heart' = 13
Probability of getting a heart = \(\frac { 13 }{ 49 } \)
(b) Number of cards which are 'a king' = 3
Probability of getting a king =\(\frac { 3 }{ 49 } \)
(c) Number of cards which are 'the 10 of hearts' = 1
Probability of getting 'the 10 of hearts' = \(\frac { 1 }{ 49 } \) 

(a) The number of drivers in the age of 25-40 years and has more than 2 accidents in the year
= 15 + 10 = 25
(b) The number of drivers the age of whose is above 40 years and has accidents more than 1 but less than 3
= 13 + 17 = 30.

Total number of subjects = 5
(i) Number of subjects in which the student gets a first class = 4
Probability that the students gets a first class \(=\frac { 4 }{ 5 } \)
(ii) Number of subjects in which the student gets a distinction = 2
Probability that the student gets a distinction  \(=\frac { 2 }{ 5 } \)
(iii) Number of subjects in which the student gets marks between 70% and 80% = 1
Probability that the students gets marks between 70% and 80% \(=\frac { 1 }{ 5 } \) 

Total number of times a die is rolled = 25
Even numbers are 2, 4, 6.
Probability of getting an even number
\(=\frac { 4+6+0 }{ 25 } =\frac { 10 }{ 25 } =\frac { 2 }{ 5 } \)
(b) Multiples of 3 are 3, 6.
Probability of getting a multiple of 3
\(=\frac { 5+0 }{ 25 } =\frac { 5 }{ 25 } =\frac { 1 }{ 5 } \)
(c) 2, 3, 5 are prime numbers.
Probability of getting a prime number
\(=\frac { 4+5+1 }{ 25 } =\frac { 10 }{ 25 } =\frac { 2 }{ 5 } \)

In the bag,
number of red balls = 5
number of white balls = 8
number of green balls = 4
number of black balls = 7
Total number of balls in the bag = 5 + 8 + 4 + 7 = 24
(i) Number of black balls = 7
Probability that the ball drawn is black =\(\frac { 7 }{ 24 } \) 
(ii) Number of balls that are not green = 5 + 8 + 7 = 20
Probability that the ball drawn is not green =\(\frac { 20 }{ 24 } \) =\(\frac { 5 }{ 6 } \)

Total number of days = 250
(i) Number of days on which the weather forecasts were correct = 175
Probability that on a given day it was correct = \(\frac { 175 }{ 250 } =\frac { 7 }{ 10 } \)
(ii) Probability that it was not correct on a given day=\(1-\frac { 7 }{ 10 } =\frac { 3 }{ 10 } \)