Probability - Self Evaluation

Probability

Self Evaluation / Assessment Questions

Note : Please write the fractions in the form a/b

Question : 1 (3 marks )

When a coin is tossed what is the probability of getting Head?

Total outcomes

number of outcomes in favour of Head =


∴Probability(H) =

Question : 2 (3 marks )

If you imagine a single digit number, what is its probability to be an even number ?


Total outcomes =

Number of outcomes in favour of Even =


∴Probability of Even number=

Question : 3 (3 marks )

If you imagine a two digit number, what is its probability to be odd ?


Total outcomes =



Number of outcomes in favour of Odd =


∴Probability

Question : 4 (3 marks )

If you imagine a two digit number, What is its possibility for being a multiple of 7 ?


Total outcomes =



Favourable outcomes =


∴Probability =

Question : 5 (3 marks )

What is the probability of a number less than 501 to be a Perfect Square?


Total outcomes =



Favourable Outcomes =


∴Probability =

Question : 6 (3 marks )

What is the probability of a number less than 201 , to be a Prime number ?


Total outcomes =



Favourable outcomes =


∴Probability =

Question : 7 (5 marks )

In a box, there are , 18 Redballs and 18 Black balls.
If you took one ball out of it blind foldedly, what is the probability of it to be a
Redball? what is the probability of it to be a
Black ball ?


Number of red balls =


Number of black balls =


∴Total number of balls =


∴Probability of Red =


∴Probability of Black =

Question : 8 (5 marks )

In a box from1 to 8 numbers are written in paper slips.
In another box numbers from, 1 to 4 are written.
If you blind foldedly took one from each box
what is the probability of sum of these slips to be
7 ?


Number of slips in the first box


Number of slips in the second box


∴Total number of pairs


Number of pairs in which the sum is 7 ?


∴ Probability =

Question : 9 (3 marks )

What is the probability of the sum of digits of a two digit number is to be 7 ?


Total number of two digit numbers =


Total number of two digit numbers whose sum of digits is 7 =


∴ Probability =

Question : 10 (9 marks )

In 10 A division there are,
20 boys and 10 girls,
In 10 B division there are ,
20 boys and 25 girls .
If one student from each class is selected randomly then ,
(1) What is the probability of both of them are boys ?
(2) What is the probability of both of them are girls ?
(3) What is the probability of one boy and one girl ?

Total students in 10 A


Total students in 10 B


∴ Total number of pairs =


Number of pairs in which both the students are boys


Number of pairs in which both the students are girls


Number of pairs in which a boy and a girl


∴ Probability of both of them are boys =


∴ Probability of both of them are girls =


∴ Probability of Boy or Girl =