Problems on Numbers Quiz Set 005

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Question 1

8 times the middle of three consecutive even numbers is 22 more than 5 times the smallest of the three numbers. What is the middle number?

 A

4.

 B

5.

 C

3.

 D

6.

Soln.
Ans: a

This is the general solution. Let the numbers be 2n - 2, 2n and 2n + 2. We are given 8 × 2n = 22 + 5 × (2n - 2).
⇒ 8 × 2n = 22 + 5 × 2n - 5 × 2.
⇒ 2n × (8 - 5) = 22 - 5 × 2, so 2n = ${22 - 5 × 2}/{8 - 5} = 4$


Question 2

When a two digit number is reversed and added to itself we get 154. The product of the digits of that number is 49. What is the number?

 A

77.

 B

78.

 C

76.

 D

79.

Soln.
Ans: a

Let the number be ab. When it is reversed and added to itself we get (10a + b) + (10b + a) = 11 × (a + b). We are given 154 = 11 × (a + b) ⇒ $a + b = 154 / 11 = 14$, so the digits are $a$ and $14 - a$. We are given their product as a × (14 - a) = 49, which is a quadratic expression that can be simplified to $(a - 7) × (7 - a) = 0$. So the number could be 77 or 77.


Question 3

What is the digit at units place: 2840 × 2492 × 6032?

 A

0.

 B

1.

 C

3.

 D

2.

Soln.
Ans: a

The digit at units place = (last digit of 2840) × (last digit of 2492) × (last digit of 6032) = 0 × 2 × 2 = 0, which = 0.


Question 4

The sum of three consecutive odd integer numbers is -2211. The middle among the three is?

 A

-737.

 B

-736.

 C

-734.

 D

-735.

Soln.
Ans: a

Let the numbers be 2n - 3, 2n - 1 and 2n + 1. The sum is 3(2n - 1) = 3 x middle. We are given 3 x middle = -2211, ⇒ middle = $-2211/3$, i.e., middle = -737.


Question 5

The sum of two numbers is 14. Their product is 45. One of the two numbers is?

 A

9.

 B

10.

 C

8.

 D

11.

Soln.
Ans: a

Let the numbers be $a$ and $14 - a$. We are given their product as a × (14 - a) = 45, which is a quadratic expression that can be simplified to $(a - 9) × (5 - a) = 0$. So the numbers could be 9 and 5.


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Creative Commons License
This Blog Post/Article "Problems on Numbers Quiz Set 005" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2017-04-07.

Posted by Parveen(Hoven),
Aptitude Trainer


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