Let the age of the class teacher = x years.
Also, let sum of ages of students = y years.
Total students in the class = 15.
The average age of students and teacher = 15 years.
(x + y) / 16 = 15
x + y = 240 ....(1)
The average age of the teacher and the students is 2 years more than that of students. Thus,
(y / 15) + 2 = 15
y =13 × 15 = 195
Put this value in equation (1),
x + y = 240
x + 195 = 240 = 45 years
English
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12 Mins English English50 Questions100 Marks60 Mins English English10 Questions20 Marks12 Mins EnglishFor different sets of datasets X and Y. correlation coefficient between X and Y, that is R and standard deviation of X and Y, that is, S(X) and S(Y) are given in A-D below. Estimate the covariance between X and Y for each dataset and arrange in ascending order.
A. R= 0.5, S(X)= 8, S(Y)= 10
B. R= 4/7, S(X)= 7, S(Y)= 9
C. R= 0.7, S(X)= 12, S(Y)= 5
D. R= 19/42, S(X)= 14, S(Y)= 6
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