The third proportional to x2-y2 and x-y is : (x + y ) (x - y) (x + y) / ( x - y)

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Question
The third proportional to x2-y2 and x-y is :
Options
A. (x + y )
B. (x - y)
C. (x + y) / ( x - y)
D. (x -y) / ( x + y)

Correct Answer

(x -y) / ( x + y)

Explanation

Let the third proportional to $(x^{2} - y^{2})$ and $(x - y)$ be z. Then,

$(x^{2} - y^{2}) : (x - y) : : (x - y) : z$

$= > (x^{2} - y^{2}) * z = {(x - y)}^{2}$

=> z= $\frac{{(x - y)}^{2}}{(x^{2} - y^{2})} = \frac{(x - y)}{(x + y)}$

Ratio and Proportion problems

Search Results

1. The ratio of male and female in a city is 7 : 8 respectively and percentage of children among male and female is 25 and 20 respectively. If number of adult females is 156800, what is the total population of the city?
Options
A. 4,12,480
B. 3,67,500
C. 5,44,700
D. 2,98,948

2. Divide Rs.6500 among A, B and C so that after spending 90%, 75% and 60% of their respective saving was in the ratio of 3: 5: 6
Options
A. A=1000, B=2000, C=1500
B. A=3000, B=1000, C=1500
C. A=3000, B=2000, C=1500
D. A=3000, B=2000, C=1000

3. What is the third proportional to 16 and 36 ?
Options
A. 81
B. 79
C. 84
D. 88

4. The number of oranges in three baskets are in the ratio of 3 : 4 : 5. In which ratio the no. of oranges in first two baskets must be increased so that the new ratio becomes 5 : 4 : 3?
Options
A. 1:3
B. 2:1
C. 3:4
D. 2:3

5. Alloy A contains 40% gold and 60% silver. Alloy B contains 35% gold and 40% silver and 25% copper. Alloys A and B are mixed in the ratio of 1:4 .What is the ratio of gold and silver in the newly formed alloy is?
Options
A. 20% and 30%
B. 36% and 44%
C. 25% and 35%
D. 49% and 36%

6. If 76 is divided into four parts proportional to 7, 5, 3, 4, then the smallest part is:
Options
A. 12
B. 15
C. 16
D. 19

7. The wages of labourers in a factory increases in the ratio 22:25 and there was a reduction in the number of labourers in the ratio 15:11. Find the original wage bill if the present bill is Rs. 5000 ?
Options
A. Rs. 5500
B. Rs. 6000
C. Rs. 6200
D. Rs. 6350

9. One year ago the ratio between Maneela?s and Shanthi?s salary was 3 : 4. The ratios of their individual salaries between last year?s and this year?s salaries are 4 : 5 and 2 : 3 respectively. At present the total of their salary is Rs. 4160. The salary of Maneela, now is?
Options
A. Rs. 1600
B. Rs. 1700
C. Rs. 1800
D. Rs. 1900

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