The mean age group of some students is 15years. When the ...
The mean age group of some students is 15years. When the age of a teacher, 45 years old, is added to the ages of the students, the mean of their ages become 18 years. Find the number of students in the group.
7
9
15
42
Correct answer is B
x \(\frac{\sum x}{N}\)
15 = \(\frac{\sum x }{N}\)
\(\sum x\) = 15N........(i)
y = \(\frac{\sum y}{Ny} = \frac{\sum x + 45}{N + 1}\)
\(\frac{18}{1} = \frac{15N + 45}{N + 1}\)
18(N + 1) = 15N + 45
18N + 18 = 15N + 45
18N - 15N = 45 - 18
3N = 27
N = \(\frac{27}{3}\)
= 9
Given that a = log 7 and b = \(\log\) 2, express log 35 in terms of a and b....
In the diagram, PR is a tangent to the circle at Q, QT//RS, ...
The marks of eight students in a test are: 3, 10, 4, 5, 14, 13, 16 and 7. Find the range ...
Evaluate \(\frac{1.25 \times 0.025}{0.05}\), correct to 1 decimal place...
Find the total surface area of a cylinder of base radius 5cm and length 7cm ( π = 3.14) ...
In the diagram, < PSR = 220o, < SPQ = 58o and < PQR = 41o. Calculate the obtuse angle QRS....
What is the circumference of latitude 0\(^o\)S if R is the radius of the earth? ...