Question Detail

Sum of two numbers is 25 and their difference is 13. Find their product.

Answer: Option C

Explanation:

Friends, this sort of question is quite important in competitive exams, whenever any question come which have relation between sum, product and difference, this formula do the magic:

$\begin{aligned} => (x+y)^2 = (x-y)^2 + 4xy \end{aligned}$

$\begin{aligned} <=> (25)^2 = (13)^2 + 4xy \end{aligned}$

$\begin{aligned} <=> 4xy = (25)^2 - (13)^2 \end{aligned}$

$\begin{aligned} <=> xy = \frac{456}{4} = 114 \end{aligned}$

1. The sum of the squares of three numbers is 138, while the sum of their products taken two at a time is 131. Their sum is

Answer: Option B

Explanation:

Let the numbers be a, b and c.
Then,

$\begin{aligned} a^2 + b^2 + c^2 = 138 \end{aligned}$
and (ab + bc + ca) = 131

$\begin{aligned} (a + b + c)^2 = a^2 + b^2 + c^2 + 2(ab + bc + ca) \end{aligned}$
= 138 + 2 x 131 = 400

$\begin{aligned} => (a + b + c) = \sqrt{400} = 20. \end{aligned}$

2. Sum of three numbers 264, If the first number be twice then second and third number be one third of the first, then the second number is

Answer: Option C

Explanation:

Let the second number is x, then first is 2x, and third is 1/3(2x)

$\begin{aligned} =>2x + x + \frac{2x}{3} = 264 <=> \frac{11x}{3} = 264 \end{aligned}$

$\begin{aligned} => x = 72 \end{aligned}$

3. If one third of one fourth of number is 15, then three tenth of number is

Answer: Option C

Explanation:

Let the number is x,

$\begin{aligned} \frac{1}{3} of\frac{1}{4} * x = 15 \end{aligned}$

$\begin{aligned} => x = 15\times 12 = 180 \end{aligned}$

$\begin{aligned} => so \frac{3}{10} \times x = \frac{3}{10} \times 180 = 54 \end{aligned}$

4. Find the number which when multiplied by 15 is increased by 196

Answer: Option C

Explanation:

Let the number be x.
Then, 15x = x + 196
=› 14 x= 196
=› x = 14.

5. Find the number, when 15 is subtracted from 7 times the number, the result is 10 more than twice of the number

Answer: Option A

Explanation:

Let the number be x.
7x -15 = 2x + 10 => 5x = 25 => x = 5

Vishnu Dilip Chalakudy 9 years ago

a + b = 25
a - b = 13
from this b = 19
a = 6
a*b = 114

Question Detail

Sum of two numbers is 25 and their difference is 13. Find their product.

1. The sum of the squares of three numbers is 138, while the sum of their products taken two at a time is 131. Their sum is

2. Sum of three numbers 264, If the first number be twice then second and third number be one third of the first, then the second number is

3. If one third of one fourth of number is 15, then three tenth of number is

4. Find the number which when multiplied by 15 is increased by 196

5. Find the number, when 15 is subtracted from 7 times the number, the result is 10 more than twice of the number

Thanks ! Your comment will be approved shortly !

Vishnu Dilip Chalakudy 9 years ago

Videos @mastguru

To Appreciate Our Effort, Please Like Us

Quantitative Aptitude

English Aptitude

Reasoning Aptitude

Computer Awareness

General Knowledge

Current Affairs

IT Officer Aptitude

Programming Aptitude

Latest Govt Jobs

Question Detail

Sum of two numbers is 25 and their difference is 13. Find their product.

1. The sum of the squares of three numbers is 138, while the sum of their products taken two at a time is 131. Their sum is

2. Sum of three numbers 264, If the first number be twice then second and third number be one third of the first, then the second number is

3. If one third of one fourth of number is 15, then three tenth of number is

4. Find the number which when multiplied by 15 is increased by 196

5. Find the number, when 15 is subtracted from 7 times the number, the result is 10 more than twice of the number

Thanks ! Your comment will be approved shortly !

Vishnu Dilip Chalakudy 9 years ago

Videos @mastguru

To Appreciate Our Effort, Please Like Us

Current Affairs

Govt Jobs

Current Affairs 15th August 2019

Current Affairs 14th August 2019

Current Affairs 13th August 2019

Current Affairs 12th August 2019

Current Affairs 11th August 2019

Junior Associates (Clerical Cadre) Jobs in SBI

Technical Jobs in NGRI

Experienced Personnel Jobs in Power Grid NRTS-I

The Punjab State Transmission Corporation Limited (PSTCL) Jobs

Energy Assistant Jobs in AP CPDCL