Practice MCQ Questions and Answer on Progressions
31.
If the Arithmetic mean of 7, 5, 13, x and 9 is 10, then the value of x is
- (A) 10
- (B) 12
- (C) 14
- (D) 16
32.
If the fifth term of a GP is 81 and first term is 16, what will be the 4th term of the GP?
- (A) 36
- (B) 18
- (C) 54
- (D) 24
33.
The first three terms of an A.P. respectively are 3y ÃÂÃÂÃÂâÃÂÃÂÃÂà1, 3y + 5 and 5y + 1. Then, y equals
- (A) -3
- (B) 4
- (C) 5
- (D) 2
34.
Let S denotes the sum of n terms of an A.P. whose first term is a. If the common difference d is given by d = S ÃÂÃÂÃÂâÃÂÃÂÃÂàk S + S then k =nn-1n-2
- (A) 1
- (B) 2
- (C) 3
- (D) None of these
35.
How many terms are there in the GP 5, 20, 80, 320........... 20480?
- (A) 5
- (B) 6
- (C) 8
- (D) 9
36.
If S denotes the sum of the first r terms of an A.P. Then, S : (S ÃÂÃÂÃÂâÃÂÃÂÃÂàS) isn3n2nn
- (A) n
- (B) 3n
- (C) 3
- (D) None of these
37.
The 7th and 21st terms of an AP are 6 and -22 respectively. Find the 26th term
- (A) -34
- (B) -32
- (C) -12
- (D) -10
38.
A bacteria gives birth to two new bacteria in each second and the life span of each bacteria is 5 seconds. The process of the reproduction is continuous until the death of the bacteria. initially there is one newly born bacteria at time t = 0, the find the total number of live bacteria just after 10 seconds :
- (A) $$\frac{{{3^{10}}}}{2}$$
- (B) 310 - 210
- (C) 243 × (35 -1)
- (D) 310 - 25
39.
If 18th and 11th term of an A.P. are in the ratio 3 : 2, then its 21st and 5th terms are in the ratio
- (A) 3 : 2
- (B) 3 : 1
- (C) 1 : 3
- (D) 2 : 3
40.
If an A.P. has a = 1, tn = 20 and sn = 399, then value of n is :
- (A) 20
- (B) 32
- (C) 38
- (D) 40