Question
The average number of books on history, polity and
geography in a library is 144, and the average number of books on history and geography is 140. If the number books on geography is 25% less than the number of books on polity, then what is the number of books on history in the library?Solution
Let the number of books on History, Polity and Geography be x, y and z respectively. Given, (x + y + z)/3 = 144 Or, x + y + z = 432 ….. (1) And, (x + z)/2 = 140 Or, x + z = 280 ….. (2) From equation 1 and 2 Number of books on polity = y = 152 Number of books on geography = 0.75 × 152 = 114 Therefore, number of books on history = 432 – (152 + 114) = 166
If moment generating function of continuous random variable X is (λ /λ−t) ;t < λ, then E(X3) equals to:
The limits of multiple correlation coefficient R1.23 are:
If price-quantity are related for base year (0) and current year (1) are
∑ : p0q0 = 260,∑ : p1q0 = 395,∑ : p0q1 = 264,∑ : p1q1 = 422, t...
 X and Y are independent normal variables with mean 50 and 80 respectively and standard deviation as 4 and 3 respectively. What is the distribution o...
These seventh decile (D7) of data set 4, 3, 10, 9, 1 is
Which one is not non-probability sample method
If random variable X follows binomial distribution with parameter n and p with mean 15 and variance 10, then the value of mode is
If each observation is halved then the coefficient of quartile deviation
Relevant for Exams:
