# Aptitude Questions : Number System Set 6

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Hello Aspirants. Welcome to Online Quantitative Aptitude Section with explanation in AffairsCloud.com. Here we are creating question sample in Number System, which is common for all the competitive exams. We have included Some questions that are repeatedly asked in bank exams !!

1. What will be the Unit digit of 27!
A.0
B.1
C.3
D.4
E.None of these
Answer – A.0
Explanation :
1*2*3*………………………………26*27
Factorial after 6 should end with 0

2. x p Ã— x q Ã— x r = 1 then p3+q3+r3 isÂ  equal to
A.0
B.1
C.pqr
D.3pqr
E.None of these
Answer – D.3pqr
Explanation :
x p Ã— x q Ã— x r = 1
x p+q+r Â = 1
x 0 = 1 => p+q+r = 1
p3+q3+r3 â€“ 3pqr = (p+q+r)(p2+q2+r2-pq-qr-rp)
p3+q3+r3 â€“ 3pqr = 0
p3+q3+r3 = 3pqr

3. If the divisor is five times the quotient and six times the remainder, if the remainder is 5 then the dividend is
A.225
B.300
C.185
D.412
E.None of these
Answer – C.185
Explanation :
Q=6, R = 5
Dividend = divisor*Q + R
Dividend = 30*6 + 5 = 180+5 = 185

4. If the sum and the product of 2 numbers are 25 and 144 respectively then the difference of the number should be
A.11
B.9
C.7
D.15
E.None of these
Answer – C.7
Explanation :
A+B = 25
AB = 24
(a-b)2 = (a+b)2 â€“ 4ab
(a-b)2 = 252 â€“ 4(144)
(a-b)2 = 625 â€“ 576
(a-b)2 = 49
a-b =Â  7

5. The sum of the two digit number is 11. The number obtained by reversing the digit is 27 Â less than the original number.Then the original number is
A.74
B.47
C.65
D.83
E.None of these
Answer – A.74
Explanation :
4+7 = 11
74-47 = 27

6. The product of 2 consecutive even number is 1224, then one of the number is
A.26
B.36
C.28
D.42
E.None of these
Answer – B.36
Explanation :
34*36 = 1224

7. 212+222+232+…………………302 = ?
A.5640
B.9455
C.6585
D.2870
E.None of these
Answer – C.6585
Explanation :
12+22+32+…………………n2 = 1/6[n(n+1)(2n+1)]
= 30*31*61/6 â€“ 20*21*41/6
= 9455 â€“ 2870 = 6585

8. A number when divided by 361 gives a remainder 47. If the Same number is divided by 19 ,the remainder is
A.18
B.11
C.9
D.13
E.None of these
Answer – C.9
Explanation :
47Ã·19=> remainder 9
Ex : 769 Ã· 361 => remainder 47
769 Ã· 19 => remainder 9

9. The respective ratio between the Â two digit of a number is 5:3, if the digit at the oneâ€™s place is twice the digit at tenâ€™s place.What is the number ?
A.63
B.21
C.12
D.Canâ€™t be determined
E.None of these
Answer – D.Canâ€™t be determined
Explanation :
2x/x = 5/3
6x = 5x

10. N is the smallest number which when added to the 2000 makes the resulting number divisible by 12, 16, 18 and 21, Then the N is
A.11
B.7
C.9
D.16
E.None of these
Answer – D.16
Explanation :
LCM of 12, 16, 18, 21 = 1008
1008*2 = 2016
N = 16

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