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20×3 is a multiple of 3 if the digit x is or or __.

Answer: 1 or 4 or 7 It is known that, when a number is a multiple of 3, if the sum of digits in the number is a multiple of 3 By equating the... View Article

3134673 is divisible by 3 and ______.

Answer: 9 3134673 is divisible by 3 and 9. Let us consider the sum of the digit of 3134673 The Sum of digits of 3134673 = 3 + 1 + 3 + 4 + 6 + 7 +... View Article

Which of the following numbers is divisible by 99 (a) 913462 (b) 114345 (c) 135792 (d) 3572406

Answer: (b) 114345 If a number is divisible is 99, it should be divisible by both 9 and 11. Consider option (a) 913462 Sum of digits = 9 + 1 +... View Article

If 6 A × B = A 8 B, then the value of A – B is (a) –2 (b) 2 (c) –3 (d) 3

Answer: (a) -2 Given that, 6 A × B = A 8 B So, AB = B Therefore A = 1 Now substitute A = 1 in the given equation 6B = A8 6B = 18 B = 18/6 B... View Article

If 5 A × A = 399, then the value of A is (a) 3 (b) 6 (c) 7 (d) 9

Answer: In the 1’s place, the product of A and A gives 9. Here, A is a number whose multiplication gives the two digit number having 9 in... View Article

If A 3 + 8 B = 150, then the value of A + B is (a) 13 (b) 12 (c) 17 (d) 15

Answer: From the question, In 1’s place, we have to add 3 + B = 0 Since B is a digit, the value of B should between 0 and 9 When you... View Article

If 5 A + B 3 = 65, then the value of A and B is (a) A = 2, B = 3 (b) A = 3, B = 2 (c) A = 2, B = 1 (d) A = 1, B = 2

Answer: (c) A = 2, B = 1 In the 1’s column A +3 = 5 When A is added with 3, it gives 5 Since A is a digit, it should be between 0 and 9... View Article

If x + y + z = 6 and z is an odd digit, then the three-digit number xyz is (a) an odd multiple of 3 (b) odd multiple of 6 (c) even multiple of 3 (d) even multiple of 9

Answer: (a) an odd multiple of 3 Given that, the sum of the digits xyz is given as x+y+z is 6, where z is an odd integer. The divisibility test... View Article

If the sum of digits of a number is divisible by three, then the number is always divisible by (a) 2 (b) 3 (c) 6 (d) 9

Answer: (b) 3 If the sum of the digits of a number is divisible by 3, then the number is also divisible by 3. Consider the number 372, then 3 + 7... View Article

A six-digit number is formed by repeating a three-digit number. For example 256256, 678678, etc. Any number of this form is divisible by (a) 7 only (b) 11 only (c) 13 only (d) 1001

Answer: (d) 1001 From the given question, the number should be of the form abcabc So the general form of abcabc is 1000000a +100000b + 1000c +... View Article

If abc is a three digit number, then the number abc – a – b – c is divisible by (a) 9 (b) 90 (c) 10 (d) 11

Answer: (a) 9 We know that the general form of abc is 100a + 10b + c Then the given number is abc - a - b - c abc - a - b - c =100a + 10b + c - a... View Article

A four-digit number 4ab5 is divisible by 55. Then the value of b – a is (a) 0 (b) 1 (c) 4 (d) 5

Answer: (b) 1 We know that the four digit number 4ab5 which is divisible by 55 is also divisible by 11 and also the factors of it. By using the... View Article

Let abc be a three digit number. Then abc + bca + cab is not divisible by (a) a + b + c (b) 3 (c) 37 (d) 9

Answer: (d) 9 The general form of abc = 100a + 10b + c The general form of bca = 100b + 10c + a The general form of cab = 100c + 10a + b By... View Article

A four-digit number aabb is divisible by 55. Then possible value(s) of b is/are (a) 0 and 2 (b) 2 and 5 (c) 0 and 5 (d) 7

Answer: (c) 0 and 5 It is known that if a four-digit number aabb is divisible by 55, then the number should be divisible by the factors of 55.... View Article

The sum of all the numbers formed by the digits x, y and z of the number xyz is divisible by (a) 11 (b) 33 (c) 37 (d) 74

Answer: (c) 37 It is known that, three numbers which can be formed by the using the digits x, y and z are xyz, yzx and zxy. The general form of... View Article

Let abc be a three-digit number. Then abc – cba is not divisible by (a) 9 (b) 11 (c) 18 (d) 33

Answer: (c) 18 The general representation of a number is as follows: For a two-digit number say AB A × 10 + B × 1 For a three-digit... View Article

The usual form of 1000a + 10b + c is (a) abc (b) abco (c) aobc (d) aboc

Answer: (c) a0bc The usual form to represent the aobc is 1000 x a + 100 x 0 + 10 x b + 1 x c, which is equal 1000a + 10b + c The general... View Article

Generalised form of a two-digit number xy is (a) x + y (b) 10x + y (c) 10x – y (d) 10y + x

Answer: (b) 10x + y The numbers are expressed as the sum of the product of it digits with the respective place value. So the generalised form of... View Article

Generalised form of a four-digit number abdc is (a) 1000 a + 100 b + 10 c + d (b) 1000 a + 100 c + 10 b + d (c) 1000 a + 100 b + 10 d + c (d) a × b × c × d

Answer: (c) 1000 a + 100 b + 10 d + c We know that, the numbers are expressed as the sum of the product of it digits with the respective place... View Article

A mixture of iron nails, salt, oil and water is provided to you. Give stepwise methods to separate each component from this mixture.

Answer: A mixture of iron nails, salt, oil and water can be separated by the following steps: Iron nails can be handpicked or removed by a... View Article