Q. If the exterior angle of a triangle is 120 degrees, what is the measure of the smallest interior angle?
A.30 degrees
B.40 degrees
C.60 degrees
D.80 degrees
Solution
The exterior angle is equal to the sum of the two opposite interior angles. If the exterior angle is 120 degrees, the smallest interior angle can be calculated as 180 - 120 = 60 degrees.
Q. If the first term of a geometric progression is x and the common ratio is 1/2, what is the sum of the first 5 terms?
A.x
B.x/2
C.x/3
D.x(1 - (1/2)^5)/(1 - 1/2)
Solution
The sum of the first n terms of a GP is given by S_n = a(1 - r^n) / (1 - r). Here, S_5 = x(1 - (1/2)^5) / (1 - 1/2) = x(1 - 1/32) / (1/2) = x(31/32) * 2 = x(62/32).
Q. If the first term of a harmonic progression is 1 and the common difference of the corresponding arithmetic progression is 2, what is the second term of the harmonic progression?
A.1/2
B.1/3
C.1/4
D.1/5
Solution
The first term is 1, and the second term's reciprocal will be 1 + 2 = 3. Therefore, the second term is 1/3.
Q. If the first term of a harmonic progression is 1 and the common difference of the corresponding arithmetic progression is 1, what is the second term of the harmonic progression?
A.1/2
B.1/3
C.1/4
D.1/5
Solution
The first term is 1, and the second term's reciprocal will be 1 + 1 = 2, so the second term is 1/2.
Q. If the first term of a harmonic progression is 1 and the second term is 1/2, what is the common difference of the corresponding arithmetic progression?
A.1/2
B.1/4
C.1/3
D.1
Solution
The reciprocals are 1 and 2, which have a common difference of 1.
Q. If the first term of a harmonic progression is 4 and the common difference of the corresponding arithmetic progression is 2, what is the second term?
A.2
B.3
C.4
D.5
Solution
The first term is 4, and the reciprocal is 1/4. The second term's reciprocal will be 1/4 + 2 = 9/4, so the second term is 4/9.
Q. If the first term of a harmonic progression is 5 and the common difference of the corresponding arithmetic progression is 2, what is the second term?
A.2
B.3
C.4
D.6
Solution
The first term in the arithmetic progression is 1/5, and the common difference is 2. Therefore, the second term in the harmonic progression is 1/(1/5 + 2) = 1/(2.2) = 5/11.
Q. If the first term of a harmonic progression is 5 and the second term is 10, what is the fourth term?
A.15
B.20
C.25
D.30
Solution
The reciprocals are 1/5 and 1/10. The common difference is -1/10. The fourth term's reciprocal will be 1/10 - 1/10 = 1/25, hence the fourth term is 25.