Question
Maria is taking a quiz that contains 3 questions, each
with 5 options. Only one option is correct for each question. If Maria guesses all the answers, what is the probability that she will get exactly 2 questions correct?Solution
ATQ, Probability of guessing the right answer for each question = 1/5 Probability of guessing the wrong answer for each question = 4/5 The probability of getting exactly 2 questions correct involves Maria guessing 2 right and 1 wrong. This can happen in (3/2) = 3 different ways So, required probability = 3 Γ (1/5 Γ 1/5 Γ 4/5) = 12/125
The average age of A and B is 22 years. If A is to be replaced by C, the average would be 21 years. The average age of C and A is 23 years. Find the age...
- A class of 20 students has an average age of 19 years. 5 new students join and the average becomes 17.5 years. Find the average age of the new students.
A number is such that when it is multiplied by 5, it gives another number which is as much above from 270 as the original number (itself) is below 270. ...
There are three distinct numbers βpβ, βqβ and βrβ. If, p = 150, (p + q) = 450 and (r β q) = 60, then determine the average of p, q and r.οΏ½...
‘N’ is the number of employees in an IT company ‘ABC’. The average age of employees working in the company is 45 years. What wil...
Out of 6 numbers, the sum of the first 5 numbers is 7 times the number. If their average is 136, then the 6th number is:
How many identical spherical marbles having a diameter of 4 cm can be made by melting a hemisphere of radius 28 cm? (Use Ο = 22/...
What is the average of the squares of the first 35 natural numbers?
The ratio of the number of cats to sheep on a farm is 5:8. The total number of cats and sheep is 91. The combined weight of all t...
The average daily income of 7 men, 11 women and 2 boys is Rs.257.50. If the average daily income of the men is Rs.10 more than that of women and the ave...
Relevant for Exams:
