Mathematics - Playing with Numbers
Exam Duration: 45 Mins Total Questions : 30
Which of the following is the L.C.M.of 36 and 72?
- (a)
36
- (b)
72
- (c)
108
- (d)
2
What is the L.C.M.of 17 and 5 ?
- (a)
105
- (b)
95
- (c)
85
- (d)
5
What is the H.C.F. of two co-prime numbers?
- (a)
1
- (b)
0
- (c)
2
- (d)
4
Which of the following is an example of an even number?
- (a)
10351
- (b)
20989
- (c)
69007
- (d)
973572
Every number is a __________ and a _________ of itself.
- (a)
factor, multiple
- (b)
prime, composite
- (c)
even, odd
- (d)
prime, twin prime
What is the H.C.F. of the two numbers equal to?
- (a)
Product of the numbers \(\div \) their L.CM
- (b)
Product of the numbers \(\times\) their L.C.M.
- (c)
Product of the numbers.
- (d)
Quotient of the numbers.
A is the 5th prime number. 8 is the 7th prime number. What is B - A ?
- (a)
6
- (b)
8
- (c)
12
- (d)
2
Which of the following is the prime factorisation of 140 ?
- (a)
2 \(\times\) 2 \(\times\)7
- (b)
2 \(\times\) 2 \(\times\)5
- (c)
2 \(\times\) 2 \(\times\)5 \(\times\) 7
- (d)
2 \(\times\) 2 \(\times\)5 \(\times\)7 \(\times\)3
What is the smallest number which when divided by 20, 25, 35 and 40 leaves a remainder of 14, 19, 29 and 34 respectively?
- (a)
1394
- (b)
1404
- (c)
1664
- (d)
1406
The L.C.M.of 64 and 48 is 192.What is the H.C.F.of these numbers?
- (a)
16
- (b)
24
- (c)
8
- (d)
12
The L.C.M of two numbers is 3718. Which of the following numbers CANNOT possibly be the H.C.F of these numbers?
- (a)
13
- (b)
26
- (c)
104
- (d)
143
Observe the following sums.
1 = 1 \(\times \) 1 = 1
1 + 3 = 2\(\times \) 2 = 4
1 + 3 + 5 = 3 \(\times \) 3 = 9
1 + 3 + 5 + 7 = 4 \(\times \) 4 = 16
1 + 3 + 5 + 7 + 9 = 5 \(\times \) 5 = 25
__________________________
__________________________
What is the result of the sum 1 + 3 + 5 + 7 + 9 + .....+15 ?
- (a)
121
- (b)
81
- (c)
100
- (d)
64
Which of the following is a factor of the number shown on the spike abacus?
- (a)
10
- (b)
7
- (c)
5
- (d)
8
Which of the following is a prime number?
- (a)
117
- (b)
171
- (c)
179
- (d)
143
What is the greatest number which divides 134 and 167 leaving 2 as remainder in each case?
- (a)
34
- (b)
37
- (c)
39
- (d)
33
If a and b are co-primes, then what is their L.C.M.?
- (a)
1
- (b)
\(\frac { a }{ b } \)
- (c)
ab
- (d)
a + b
67,61, p, q, r, s, 41. is an arrangement of prime numbers In decreasing order. Among the following, which is the number 53?
- (a)
p
- (b)
r
- (c)
q
- (d)
s
Given that (p + 3) is the highest common factor of 81 and 108, find the value of p.
- (a)
6
- (b)
9
- (c)
12
- (d)
24
What is the possible value of the product of P and Q, given that their H.C.F is 12 and L.C.M is 120 ?
- (a)
1200
- (b)
120
- (c)
1440
- (d)
144
A number is divisible by both 5 and 12. By which other number will that number be always divisible?
- (a)
72
- (b)
60
- (c)
62
- (d)
42
The number (11, 13) are _______ numbers.
- (a)
Co-prime
- (b)
Prime
- (c)
Both prime and co-prime
- (d)
None of these
The HCF of two consecutive odd numbers is________
- (a)
2
- (b)
0
- (c)
4
- (d)
1
Observe the following patterns. Then find the sum of 1 + 3 + 5 + 7 + 9 + ... + 19.
1 = 1 \(\times \) 1 = 1
1 + 3 = 2\(\times \) 2 = 4
1 + 3 + 5 = 3 \(\times \) 3 = 9
1 + 3 + 5 + 7 = 4 \(\times \) 4 = 16
1 + 3 + 5 + 7 + 9 = 5 \(\times \) 5 = 25
__________________________
__________________________
- (a)
121
- (b)
81
- (c)
100
- (d)
64
The co-prime numbers from the following pairs, are________
- (a)
7 and 63
- (b)
36 and 25
- (c)
35 and 21
- (d)
63 and 81
If 5476a is divisible by 3, then what can be the least value of a?
- (a)
1
- (b)
2
- (c)
3
- (d)
6
Find the greatest number which will divide the greatest 3-digit number and the greatest 4-digit number exactly.
- (a)
9
- (b)
8
- (c)
7
- (d)
3
State 'T' for true and 'F' for false.
(i) If an even number is divided by 2, the quotient is always odd.
(ii) All even numbers are composite numbers.
(iii) The LCM of two co-prime numbers cannot be equal to their product.
(iv) Every number is a factor of itself.
- (a)
i ii iii iv T T F F - (b)
i ii iii iv F F F T - (c)
i ii iii iv T F T T - (d)
i ii iii iv F F T T
Fill in the blanks.
(i) The HCF of two co-prime numbers isP.
(ii) Two natural numbers which have no common factor except 1 are called Q numbers.
(iii) If a number is divisible by 9, then sum of its digits must be divisible by R.
- (a)
P Q R 1 prime 3 - (b)
P Q R 1 co-prime 9 - (c)
P Q R 3 prime 9 - (d)
P Q R 1 prime 9
Find the value of a + b + c, if 373a is divisible by 9, 473b is divisible by 11 and 371C is divisible by 6.
- (a)
7
- (b)
6
- (c)
0
- (d)
9
Match the following
Column I | Column II |
(i) 49 | (p) Multiple of 3 |
(ii) 25 | (q) Multiple of 4 |
(iii) 16 | (r) Multiple of 7 |
(iv) 39 | (s) Multiple of 5 |
- (a)
i ii iii iv (s) (p) (r) (q) - (b)
i ii iii iv (r) (s) (q) (p) - (c)
i ii iii iv (s) (r) (p) (q) - (d)
i ii iii iv (p) (q) (r) (s)