Problems on Numbers Quiz Set 015

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Question 1

The sum of two numbers is 11. Their product is 28. One of the two numbers is?

 A

7.

 B

8.

 C

6.

 D

9.

Soln.
Ans: a

Let the numbers be $a$ and $11 - a$. We are given their product as a × (11 - a) = 28, which is a quadratic expression that can be simplified to $(a - 7) × (4 - a) = 0$. So the numbers could be 7 and 4.


Question 2

The sum of three consecutive even integer numbers is 672. The middle among the three is?

 A

224.

 B

225.

 C

223.

 D

226.

Soln.
Ans: a

Let the numbers be 2n - 2, 2n and 2n + 2. The sum is 6n = 3 x 2n = 3 x middle. We are given 3 x middle = 672, ⇒ middle = $672/3$, i.e., middle = 224.


Question 3

How many odd numbers are there between -1570 and 2426?

 A

1998.

 B

1999.

 C

1997.

 D

2000.

Soln.
Ans: a

Odd numbers are in an AP. First term $a = -1569$, common difference $d = 2$, the last term $t_n$ is given as 2425. By the AP formula, $2425 = -1569 + (n - 1) × 2$ ⇒ $n = 1 + {{2425 - (-1569)}/2} = 1998$.


Question 4

Which term of this arithmetic series is zero: 81, 72, 63 ...?

 A

10.

 B

11.

 C

9.

 D

12.

Soln.
Ans: a

The first term is 81, common difference is d = -9, n-th term is 0. So $0 = 81 + (n - 1) × -9$ which gives $n = 1 + {81/9} = 10$.


Question 5

The sum of two numbers is 18. Their difference is 8. They are in the ratio?

 A

$2{3/5}$.

 B

$4{1/2}$.

 C

$1{1/7}$.

 D

4.

Soln.
Ans: a

Let the numbers be a and b, and let their ratio be k such that $a/b = k$. We are given $a + b = 18$ ⇒ $b(k + 1) = 18$. Similarly, from the difference we can obtain $b(k - 1) = 8$. Dividing we get ${k + 1}/{k - 1} = 18/8$. By componendo and dividendo, $k = {18 + 8}/{18 - 8}$ = ${13/5}$, which is same as: $2{3/5}$.


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This Blog Post/Article "Problems on Numbers Quiz Set 015" 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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