Number System Quantitative Aptitude Questions & Answers

Directions : In each of the following questions, out of the given alternatives, choose the correct answer.
1. On subtracting 6 from one-fifth of a number, the result is 12. What is the number ?
(a) 65
(b) 51
(c) 90
(d) 75

View Answer

Answer : (c) 90

Explanation :

Let the number be x.
So, x/5 - 6 = 12
=> x/5 = 18
=> x = 90

2. What is the place value of 9 in 5981 ?
(a) 9
(b) 900
(c) 90
(d) 9000

View Answer

Answer : (b) 900

Explanation :

The place value of 9 in the numeral is 9 * 100 = 900.

3. A bucket full of water weights 50 kg, while half-filled bucket weights 30 kg. Then what is the weight of the empty bucket ?
(a) 25 kg
(b) 10 kg
(c) 20 kg
(d) 15 kg

View Answer

Answer : (b) 10 kg

Explanation :

Given weight of bucket + full water = 50 kg
and weight of bucket + half water = 30 kg
Thus weight of half water = (50-30)kg = 20 kg
So, weight of empty bucket = (30-20)kg = 10 kg

4. A number when multiplied by 21 is increased by 420. Find the number.
(a) 20
(b) 19
(c) 22
(d) 21

View Answer

Answer : (d) 21

Explanation :

Let x be the required number.
Then, 21x = x + 420
=> 21x - x = 420
=> x = 420/21 = 21

5. What least number should be added to 4152 to obtain a number which is completely divisible by 17 ?
(a) 15
(b) 11
(c) 13
(d) 17

View Answer

Answer : (c) 13

Explanation :

When we divide 4152 by 17 we get 244 as the quotient and 4 as the remainder.
If we subtract the remainder from the divisor then we will get our answer.
Hence the the required number is 17 - 4 = 13 should be added to 4152 for it to be completely divisible by 17 .

6. 9187 - ? = 3429 - 1385
(a) 4373
(b) 3467
(c) 5391
(d) 7143

View Answer

Answer : (d) 7143

Explanation :

Let x be the required number.
So, 9187 - x = 3429 - 1385
or 9187 - x = 2044
or x = 9187 - 2044 = 7143

7. The smallest five digit number which is 31 is :
(a) 10031
(b) 10131
(c) 10089
(d) 10013

View Answer

Answer : (d) 10013

Explanation :

The smallest five digit number is 10000.
On dividing 10000 by 31 we get 322 as the quotient and 18 as remainder.
So 31 - 18 = 13 must be added to the five digit number to get our answer.
Thus 10000 + 13 = 10013 is completely divisible by 31.

8. The difference between place value and face value of 4 in the numeral 4159 is :
(a) 3996
(b) 3986
(c) 3896
(d) 4000

View Answer

Answer : (a) 3996

Explanation :

Place value of 4 is 4 * 1000 = 4000
and face value is 4.
So, the required difference is 4000 - 4 = 3996

9. Product of two number is 128. If the greater number is two times the smaller number, then what is the greater number ?
(a) 16
(b) 18
(c) 12
(d) 14

View Answer

Answer : (a) 16

Explanation :

Let the smaller number be x, then greater number is 2x.
So x * 2x = 128
=> 2x² = 128
=> x² = 128/2 = 64
=> x = 8
Thus the bigger number is 2x = 2 * 8 = 16.

10. What is the place value of 0 in the numeral 9086 ?
(a) 100
(b) 0
(c) 9000
(d) 80

View Answer

Answer : (b) 0

Explanation :

The place value of zero '0' is always 0. So here the place value is also 0.