Find the average of the first four prime numbers greater than10
20
19
17
15
Correct answer is D
First four prime numbers greater than 10 are 11, 13, 17, 19
The average \(= \frac{11+13+17+19}{4}=15\)
In the diagram, O is the centre of the circle where OS//QR and ∠SOR = 35o
35o
45o
55o
70o
Correct answer is C
∠SOR = ∠ORQ alternate angle.
Also ∠OQR = ∠OQR (Base angle of isosceles)
∠QOR = 108 – 2(35o) = 180 - 70o - 110o ∠QPR = 1/2QOR = 1/2(110o) ∠QPR + 55o (theorem angle at center is twice angle at circumference)
A point X is on the bearing 342° from a point Y. What is the bearing of Y from X?
342o
252o
198o
162o
Correct answer is D
If x is the bearing 342° from a point y
= 360° - 342° = 18°
The bearing of y from x = 180° - 18° = 162°
Find the mean deviation of 6, 7, 8, 9, 10
1.2
1.5
2
8
Correct answer is A
\(\begin{matrix}
x & x-m & |x-m| \\
6 & -2 & 2 \\
7 & -1 & 1 \\
8 & 0 & 0 \\
9 & 1 & 1 \\
10 & 2 & 2 \\
& & 6
\end{matrix}
\)
Mean deviation\(=\frac{\sum|x-m|}{n}=\frac{6}{5} = 1.2\)
In the diagram, KS is a tangent to the circle centre O at R and ∠ROQ = 80°. Find ∠QRS.
90o
80o
50o
40o
Correct answer is D
QOP = 180 - 100(straight line angle) → 80°
OPQ and OQP are isosceles of 40° each.
∠QRS = ∠RPQ (theorem: angle in the alternate segment are equal)
∠RPQ = 40°
∠QRS = 40°
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