Mathematics
Number System
A two-digit number is 53. What is the absolute difference between the number and the number formed by reversing its digits?
A. 9
B. 18
C. 2
D. 27
Correct Answer: B
Reversed number = 35. Absolute difference = |53 - 35| = 18.
Mathematics
Number System
Find the next number in the series: 7, 14, 28, 56, 112, ?
A. 226
B. 224
C. 114
D. 112
Correct Answer: B
Each term is multiplied by 2. Therefore 112 × 2 = 224.
Mathematics
Number System
Find the next term: 82, 87, 85, 90, 88, 93, ?
A. 98
B. 86
C. 93
D. 91
Correct Answer: D
The operations alternate +5, -2. After the last +5, subtract 2: 93 - 2 = 91.
Mathematics
Number System
Find the next term: 12, 19, 38, 75, ?
A. 141
B. 61
C. 125
D. 136
Correct Answer: D
Each term is n³ + 11. Thus the next term is 5³ + 11 = 136.
Mathematics
Number System
Find the LCM of 16 and 26.
A. 208
B. 416
C. 210
D. 26
Correct Answer: A
LCM = (16 × 26) ÷ HCF(16,26) = 208.
Mathematics
Number System
What is the least positive number exactly divisible by 13, 4, and 6?
A. 156
B. 160
C. 13
D. 312
Correct Answer: A
The required number is LCM(13, 4, 6) = 156.
Mathematics
Number System
Find the next number: 7, 17, 37, 77, 157, ?
A. 314
B. 317
C. 320
D. 315
Correct Answer: B
Each term is obtained by ×2 + 3. So 157 × 2 + 3 = 317.
Mathematics
Number System
How many integers from 35 to 370, inclusive, are divisible by 14?
A. 23
B. 24
C. 25
D. 26
Correct Answer: B
Count = ⌊370/14⌋ - ⌊(35-1)/14⌋ = 26 - 2 = 24.
Mathematics
Number System
Find the next number in the series: 5, 15, 45, 135, 405, ?
A. 1218
B. 1215
C. 408
D. 405
Correct Answer: B
Each term is multiplied by 3. Therefore 405 × 3 = 1215.
Mathematics
Number System
Find the next term in the series: 23, 36, 51, 68, 87, ?
A. 127
B. 108
C. 110
D. 106
Correct Answer: B
The first differences are [13, 15, 17, 19]; their second difference is constant at 2. Continuing the pattern gives 108.
Mathematics
Number System
What is the greatest multiple of 10 that is less than 4822?
A. 4810
B. 4820
C. 4821
D. 4830
Correct Answer: B
4822 ÷ 10 has integer quotient 482; 10 × 482 = 4820.
Mathematics
Number System
Find the next number: 11, 36, 111, 336, 1011, ?
A. 3033
B. 3339
C. 3039
D. 3036
Correct Answer: D
Each term is obtained by ×3 + 3. So 1011 × 3 + 3 = 3036.
Mathematics
Number System
Find the next number: 3, 8, 18, 38, 78, ?
A. 158
B. 173
C. 160
D. 156
Correct Answer: A
Each term is obtained by ×2 + 2. So 78 × 2 + 2 = 158.
Mathematics
Number System
Find the next term: 13, 20, 39, 76, ?
A. 137
B. 125
C. 142
D. 62
Correct Answer: A
Each term is n³ + 12. Thus the next term is 5³ + 12 = 137.
Mathematics
Number System
How many positive divisors does 175 have?
A. 5
B. 8
C. 7
D. 6
Correct Answer: D
175 = 7^1 × 5^2. Number of divisors = (1+1)(2+1) = 6.
Mathematics
Number System
Find the missing number: 87, 92, ?, 102, 107, 112
A. 102
B. 107
C. 92
D. 97
Correct Answer: D
This is an arithmetic series with common difference 5; the missing term is 97.
Mathematics
Number System
What digit x makes the number 567x divisible by 9?
A. 5
B. 0
C. 1
D. 3
Correct Answer: B
A number is divisible by 9 when its digit sum is divisible by 9. Thus 5+6+7+x must be a multiple of 9, giving x = 0.
Mathematics
Number System
How many trailing zeros are there in 128! ?
A. 31
B. 30
C. 12
D. 32
Correct Answer: A
Trailing zeros = ⌊128/5⌋ + ⌊128/25⌋ + ... = 25 + 5 + 1 = 31.
Mathematics
Number System
What least number must be added to 343 so that the result is exactly divisible by 17?
A. 3
B. 31
C. 14
D. 15
Correct Answer: C
343 leaves remainder 3 on division by 17. Add 17 - 3 = 14.
Mathematics
Number System
Find the next number: 12, 16, 25, 41, 66, ?
A. 91
B. 96
C. 102
D. 108
Correct Answer: C
The increments are consecutive squares: 4, 9, 16, 25; next add 6² = 36. So the answer is 102.