1) 441, 484,?,576, 625
A) 492
C) 526
B) 507
D) 529
Ans-The pattern followed here is,
Given numbers are the squares of the 21, 22, 23, and so on.
441 = 21²;
484 = 22²;
529 = 23²;
576 = 24²;
625 = 25²;
Hence, "529" is the correct answer.
2) 1, 27, 125, 343, ?
A) 400
C) 654
B) 729
D) 967
Ans-
1 = 1³ ;
27 = 3³ ;
125 = 5³ ;
729 = 9³ ;
Hence, "729" is the correct answer.
3) 69, 55, 26, 13, ?
A) 4
C) 8
B) 20
D) 7
Ans-
(6×9)+1=55 ;
(5×5)+1=26 ;
(2×6)+1=13;
(1×3)+1=4;
Hence, "4" is the correct answer.
4) 256, ?, 324, 361
A) 286
C) 265
B) 275
D) 289
Ans-
16² = 256
17² = 289
18² = 324
19² = 361
Hence, "289" is the correct answer.
5) Find the 6th for the series: 3, 9, 27, 81.....
A) 653
C) 729
B) 700
D) 500
Ans- The correct option is B 729
The given sequence is 3, 9, 27, 81…
Let us divide each term of the sequence by the term preceding it:
The 4th term of the sequence = 81
The 5th term of the sequence = 3×( 4th term of the sequence) = 3×81 = 243.
So, the 6th term of the sequence = 3x(5th term of the sequence) = 3x 243 = 729.
6) Find the sum upto to 6th term of the series: 3, 9, 27, 81,.....
A) 1096
C) 1098
B) 1092
D) 2000.
Ans-
3¹ + 3² + 3³ + 3⁴ + 3⁵ + 3⁶
a = 3 r = 3 n = 6
=a\{(r ^ n - 1) / (r - 1)\}
=3\{(3 ^ 6 - 1) / (3 - 1)\}
=1092.
7) 8, 64, 216, 512, ?
A) 1000
C) 987
B) 576
D) 888
Ans- The pattern followed by the given number series is
0 × (0²) = 0
2× (2²) = 8
4 × (4²) = 64
6× (6²) = 216
8 × (8²) = 512
10 × (10²) = 1000
The required result will be 1000.
8) 8, 16, 24, 40, 64, ?
A) 100
C) 96
B) 98
D) 104
Ans-
8+8=16,
16+ 8 = 24,
24 +16= 40,
40+24= 64
64+40=104
The required result will be 104.
9) Find the 50th term of the series 1, 4, 7,...
A) 134
C) 190
B) 148
D) 156.
Ans- First term = a = 1
Common difference = d = 4 - 1 = 3
Number of terms = n = 50
50th term = a₅₀
aₙ = a + (n - 1) d
⇒ aₙ = 1 + (50 - 1) 3
⇒ aₙ = 1 + 49 (3)
⇒ aₙ = 1 + 147
⇒ aₙ = 148
∴ The 48th term of the AP is 148
10) Find the sum upto 50th term of the series 1, 4, 7,....
A) 3700
C) 3725
B) 3750
D) 3755
Ans- a = 1
d = 4-1=3
n = 50
using Sn = n (2a + (n-1)d]
S50 = 50 [2+ 2 49×3]
25 (2 + 147]
= 25 × 149
S50 = 3725
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