1. 1
2. 9
3. 3
4. 15
Answer : Option 3
Among the given options, 3 is an odd prime number. Therefore, the answer is option 3.
2. What least digit should come in place of # in the 9 digit number 15549#325, for which the number is divisible by 3?
1. 0
2. 1
3. 2
4. Any of these
Answer : Option 3
A number if divisible by 3 if sum of digits is multiple of 3. In 15549#325,
Sum of the digits= 1 + 5 + 5 + 4 + 9 + # + 3 + 2 + 5 = 34 + # = 34 + 2 = 36 which is divisible by 3.
3. What is the product of smallest 15 whole numbers?
1. 1
2. 0
3. 25
4. 60
Answer : Option 2
Smallest 15 whole numbers are 0, 1, 2, 3, 4,.....14. As these numbers contain a zero, so, product will be zero. So, answer is option 2.
4. What is the sum of first 10 perfect cubes?
1. 3025
2. 5625
3. 1225
4. None of these
Answer : Option 1
Sum of 1st 10 perfect cubes :- = 13 + 23 + 33 ______ + 103 = (10(10+1)/2)2 = 3025 Hence, the correct answer is option 1
5. What is the difference between the greatest 5 digit number and the smallest 5 digit number?
1. 99998
2. 89999
3. 89990
4. 99990
Answer : Option 2
The greatest 5 digit number = 99999
Smallest 5 digit number = 10000.
The required difference = 99999 – 10000 = 89999
So, the answer is option 2.
6. There are 20 people in a party. If every person shakes hand with every other person, what is the total number of handshakes?
1. 180
2. 155
3. 145
4. 190
Answer : Option 4
1st person will shake hand with 19 other persons. 2nd person will shake hand with remaining 18 persons, and so on.
Therefore, total number of handshakes.
= 19 + 18 + 17+ ……………………+ 3 + 2 + 1 = Σ19 =(19(19+1)/2) =190
So, the correct answer is option 4.
7. A 107 digit number is formed by writing first 58 natural numbers next to each other. Find the remainder when number is divided by 8.
Source: safalta
1. 6
2. 10
3. 4
4. 9
Answer : Option 1
To find remainder by 8, we only divide the number formed by the last 3 digit by 8. The last 3 digits would give the number 758. The remainder when 758 is divided by 8 = 6. So, answer is option 1.
8. The five digit number 7500A8 is divisible by 4. How many values of A are possible?
1. 0
2. 3
3. 5
4. 4
Answer : Option 3
To find divisibility by 4, we need to consider last two digits of the number, these should be divisible by 4. Hence, A can take values equal to 0, 2, 4, 6 and 8. Therefore 5 values are possible. So, the correct answer is option 3.
9. What is the sum of this series 1 + 1 + 2 + 8 + 3+ 27 + 4 + 64 +_______10 + 1000?
1. 308
2. 3008
3. 3800
4. 3080
Answer : Option 4
Here, we are given a combination of two series
(1 + 2 + 3 + 4 +.....................+10) + (1 + 8 + 27 + 64 +............+1000)
= (1 + 2 + 3 + 4 +.....................+10) + (1 +2^3 +3^3 +4^3 +.................+10^3)
(10(10+1)/2) + ((10 × 11)/2)2 = 3080. So, correct answer is option 4.
10. Which one of the following is not a rational number?
1. 0.2333
2. 0.56666
3. √3
4. 7
Answer : Option 3
Here, 0.2333, 0.56666 and 7 are rational numbers as these can be represented in the form p/q.√3 is not a rational number, therefore answer is option