Aptitude - Numbers

Exercise : Numbers - General Questions
21.
Which of the following number is divisible by 24 ?
35718
63810
537804
3125736
Answer: Option
Explanation:

24 = 3 x8, where 3 and 8 co-prime.

Clearly, 35718 is not divisible by 8, as 718 is not divisible by 8.

Similarly, 63810 is not divisible by 8 and 537804 is not divisible by 8.

Consider option (D),

Sum of digits = (3 + 1 + 2 + 5 + 7 + 3 + 6) = 27, which is divisible by 3.

Also, 736 is divisible by 8.

3125736 is divisible by (3 x 8), i.e., 24.


22.
753 x 753 + 247 x 247 - 753 x 247 = ?
753 x 753 x 753 + 247 x 247 x 247
1
1000
1
506
253
500
None of these
Answer: Option
Explanation:
Given Exp. = (a2 + b2 - ab) = 1 = 1 = 1
(a3 + b3) (a + b) (753 + 247) 1000

23.
(?) + 3699 + 1985 - 2047 = 31111
34748
27474
30154
27574
None of these
Answer: Option
Explanation:

x + 3699 + 1985 - 2047 = 31111

   x + 3699 + 1985 = 31111 + 2047

   x + 5684 = 33158

   x = 33158 - 5684 = 27474.


24.
If the number 481 * 673 is completely divisible by 9, then the smallest whole number in place of * will be:
2
5
6
7
None of these
Answer: Option
Explanation:

Sum of digits = (4 + 8 + 1 + x + 6 + 7 + 3) = (29 + x), which must be divisible by 9.

   x = 7.


25.
The difference between the local value and the face value of 7 in the numeral 32675149 is
75142
64851
5149
69993
None of these
Answer: Option
Explanation:
(Local value of 7) - (Face value of 7) = (70000 - 7) = 69993